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\multicolumn{2}{|c|}{\LARGE\bf THE\hspace*{1cm}STAR\hspace*{1cm}FORMATION\hspace*{1cm}NEWSLETTER} \\ [0.3cm]
\multicolumn{2}{|c|}{\large\em An electronic publication dedicated to early stellar evolution and molecular clouds} \\ [0.3cm]
{\hspace*{0.8cm} No. 211 --- 18 Jul 2010 } & \multicolumn{1}{r|}{Editor: Bo Reipurth (reipurth@ifa.hawaii.edu)\hspace*{0.8cm}} \\ [-0.1cm]
& \\ \hline
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%{\Large\em From the Editor}
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\begin{center}
{\Large\em Abstracts of recently accepted papers}
\end{center}
\vspace*{0.6cm}
{\large\bf{The Green Bank Telescope Galactic H\,{\small \bf II} Region Discovery Survey}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ T. M. Bania$^1$, L. D. Anderson$^1,2$, Dana S. Balser$^3$ and
R. T. Rood$^4$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Astronomy Department,
725 Commonwealth Ave., Boston University, Boston MA 02215, USA} \\
$^2$ {Current Address: Laboratoire d'Astrophysique de
Marseille (UMR 6110 CNRS \& Universit\'e de Provence), 38 rue F.
Joliot-Curie, 13388 Marseille Cedex 13, France} \\
$^3$ {National Radio Astronomy Observatory, 520 Edgemont Road,
Charlottesville VA, 22903-2475, USA} \\
$^4$ {Astronomy Department, University of Virginia, P.O. Box 3818,
Charlottesville VA 22903-0818, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: bania {\em at} bu.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\newcommand{\gl}{\ensuremath{\ell}}
\newcommand{\gb}{\ensuremath{{\it b}}}
\newcommand{\cm}{\ensuremath{\,{cm}}}
\newcommand{\pc}{\ensuremath{\,{pc}}}
\newcommand{\kpc}{\ensuremath{\,{kpc}}}
\newcommand{\microns}{\ensuremath{\,\mu{\rm m}}}
\newcommand{\hii}{{H\,{\small II}}}
\newcommand{\degr}{\ensuremath{\,^\circ}}
%% Within the following brackets you place your text:
{
We discovered a large population of previously unknown Galactic \hii\
regions by using the Green Bank Telescope to detect their hydrogen
radio recombination line emission. Since the interstellar medium is
optically thin at 3\cm\ wavelength, we can detect \hii\ regions across
the entire Galactic disk. Our targets were selected based on
spatially coincident 24\microns\ and 21\cm\ continuum emission. For the
Galactic zone $-16\,\degr \leq \gl \leq 67\,\degr$ and $\vert \gb
\vert \leq 1\,\degr$ we detected 602 discrete recombination line
components from 448 lines of sight, 95\% of the sample targets, which
more than doubles the number of known \hii regions in this part of the
Milky Way. We found 25 new first quadrant nebulae with negative LSR
velocities, placing them beyond the Solar orbit. Because we can
detect all nebulae inside the Solar orbit that are ionized by O-stars,
the Discovery Survey targets, when combined with existing \hii\ region
catalogs, give a more accurate census of Galactic \hii regions and
their properties. The distribution of \hii\ regions across the
Galactic disk shows strong, narrow ($\sim$\,1 kpc wide) peaks at
Galactic radii of 4.3 and 6.0 kpc. The longitude-velocity
distribution of \hii\ regions now gives unambiguous evidence for
Galactic structure, including the kinematic signatures of the radial
peaks in the spatial distribution, a concentration of nebulae at the
end of the Galactic Bar, and nebulae located on the kinematic locus of
the 3\kpc\ Arm.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJLett. (718, L106-L111) }
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{IRS Scan-Mapping of the Wasp-Waist Nebula (IRAS 16253$-$2429):
I. Derivation of Shock Conditions from H$_2$ Emission and Discovery of 11.3 $\mu$m PAH Absorption}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{M. Barsony$^{1,2}$, G.A. Wolf-Chase$^{3,4}$, D. Ciardi$^5$, \& J. O'Linger$^6$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Physics \& Astronomy, San Francisco State University, 1600 Holloway Drive, San Francisco, CA 94132, USA} \\
$^2$ {Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA}\\
$^3$ {Astronomy Department, Adler Planetarium, 1300 South Lake Shore Drive, Chicago, IL 60605, USA} \\
$^4$ {Dep't. of Astronomy \& Astrophysics, University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637, USA}\\
$^5$ {NASA Exoplanet Science Institute/Caltech, 770 S. Wilson Ave., MS 100-22, Pasadena, CA 91125, USA}\\
$^6$ {Spitzer Science Center, California Institute of Technology MS314-6, Pasadena, CA 91125, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: mbarsony {\em at} stars.sfsu.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{The outflow driven by the Class 0 protostar, IRAS 16253$-$2429, is
associated with bipolar cavities visible in scattered mid-infrared
light, which we refer to as the Wasp-Waist Nebula. InfraRed
Spectometer (IRS) scan mapping with the {\it Spitzer Space
Telescope} of a $\sim$ 1$^{\prime}\times 2^{\prime}$ area centered
on the protostar was carried out. The outflow is imaged in six pure
rotational (0-0 S(2) through 0-0 S(7)) H$_2$ lines, revealing a
distinct, S-shaped morphology in all maps. A source map in the 11.3
$\mu$m PAH (polycyclic aromatic hydrocarbon) feature is presented in
which the protostellar envelope appears in absorption. This is the
first detection of absorption in the 11.3 $\mu$m PAH feature.
Spatially resolved excitation analysis of positions in the blue- and
red-shifted outflow lobes, with extinction-corrections determined
from archival {\it Spitzer} 8 $\mu$m imaging, shows remarkably
constant temperatures of $\sim$1000 K in the shocked gas. The
radiated luminosity in the observed H$_2$ transitions is found to be
1.94 $\pm$ 0.05 $\times$ 10$^{-5}$ L$_{\odot}$ in the red-shifted
lobe and 1.86 $\pm$ 0.04 $\times$ 10$^{-5}$ L$_{\odot}$ in the
blue-shifted lobe. These values are comparable to the mechanical
luminosity of the flow. By contrast, the mass of hot (T$\sim$1000K)
H$_2$ gas is 7.95 $\pm$ 0.19 $\times$ 10$^{-7}$ M$_{\odot}$ in the
red-shifted lobe and 5.78 $\pm$ 0.17 $\times$ 10$^{-7}$ M$_{\odot}$
in the blue-shifted lobe. This is just a tiny fraction, of order
10$^{-3}$, of the gas in the the cold (30K), swept-up gas mass
derived from millimeter CO observations. The H$_2$ {\it ortho}/{\it
para} ratio of 3:1 found at all mapped points in this flow
suggests previous passages of shocks through the gas. Comparison of
the H$_2$ data with detailed shock models of Wilgenbus et al. (2000)
shows the emitting gas is passing through Jump (J-type) shocks.
Pre-shock densities of 10$^4$ cm$^{-3}\le$ n$_H\ \le$ 10$^5$
cm$^{-3}$ are inferred for the red-shifted lobe and n$_H\le$ 10$^3$
cm$^{-3}$ for the blue-shifted lobe. Shock velocities are 5 km
s$^{-1}\le\ v_s\ \le$ 10 km s$^{-1}$ for the red-shifted gas and
$v_s=$ 10 km s$^{-1}$ for the blue-shifted gas. Initial transverse
(to the shock) magnetic field strengths for the red-shifted lobe are
in the range 10$\mu$G$-$32$\mu$G, and just 3$\mu$G for the
blue-shifted lobe. A cookbook for using the CUBISM contributed
software for IRS spectral mapping data is presented in the
Appendix.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Ap. J. }
%% If preprints are available on the WWW you can give the web
{\tt http://physics.sfsu.edu/$\sim$mbarsony/html/pubs.html}
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{The 2008 outburst in the young stellar system Z~CMa: I.
Evidence of an enhanced bipolar wind on the AU-scale}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{M.~Benisty$^{1}$, F.~Malbet$^{2}$, C.~Dougados$^{2}$,
A.~Natta${^1}$, J-B.~Le~Bouquin$^2$, F.~Massi$^1$, M.~Bonnefoy$^2$,
J.~Bouvier$^2$, G.~Chauvin$^2$, O.~Chesneau$^3$,
P.J.V.~Garcia$^{2,4}$, K.~Grankin$^5$, A.~Isella$^6$, T.~Ratzka$^7$,
E.~Tatulli$^2$, L.~Testi$^8$, G.~Weigelt$^9$, E.T.~Whelan$^2$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {INAF-Osservatorio Astrofisico di Arcetri, Largo E.~Fermi~5, 50125
Firenze, Italy}\\
$^2$ {Laboratoire d'Astrophysique de Grenoble, 414 rue de la
piscine, 38400 St Martin d'H\`eres, France}\\
$^3$ {Laboratoire A.~H.~Fizeau, UMR~6525, Parc Valrose, 06108 Nice Cedex 02, France}\\
$^4$ {Universidade do Porto, SIM Unidade
FCT 4006, Rua Dr. Roberto Frias, s/n P-4200-465 Porto, Portugal}\\
$^5$ {Crimean Astrophysical Observatory, 98409 Nauchny, Crimea, Ukraine}\\
$^6$ {Caltech, MC 249-17, 1200 East California Blvd, Pasadena, CA 91125, USA}\\
$^7$ {Universit\"ats-Sternwarte M\"unchen Scheinerstr. 1. 81679
M\"unchen, Germany}\\
$^8$ {European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748
Garching, Germany}\\
$^9$ {Max Planck Institut f\"ur Radioastronomie, Auf dem H\"ugel 69, 53121
Bonn, Germany}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: benisty {\em at} arcetri.astro.it}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{Accretion is a fundamental process in star formation. Although the
time evolution of accretion remains a matter of debate,
observations and modelling studies suggest that episodic outbursts of
strong accretion may dominate the formation of the central
protostar. Observing young stellar objects during these elevated
accretion states is crucial to understanding the origin of unsteady
accretion.\\
Z~CMa is a pre-main-sequence binary system composed of an embedded
Herbig Be star, undergoing photometric outbursts, and a FU~Orionis
star. This system therefore provides a unique opportunity to study
unsteady accretion processes. The Herbig Be component recently
underwent its largest optical photometric outburst detected so far. We
aim to constrain the origin of this outburst by studying the
emission region of the HI Br$_{\gamma}$ line, a powerful tracer of
accretion/ejection processes on the AU-scale in young stars. \\
Using the AMBER/VLTI instrument at spectral resolutions of 1500 and
12 000, we performed spatially and spectrally resolved
interferometric observations
of the hot gas emitting across the Br$_{\gamma}$ emission line, during and
after the outburst. From the visibilities and differential phases,
we derive characteristic sizes for the Br$_{\gamma}$ emission and
spectro-astrometric measurements across the line, with respect to the
continuum. \\
We find that the line profile, the
astrometric signal, and the visibilities are inconsistent with the
signature of either a Keplerian disk or infall of matter. They
are, instead, evidence of a bipolar wind, maybe partly seen through a disk
hole inside the dust sublimation radius. The disappearance of the
Br$_{\gamma}$ emission
line after the outburst suggests that the outburst is related to a
period of strong mass loss rather than a change of the extinction along
the line of sight. \\
Apart from the photometric increase of the system, the main consequence of the
outburst is to trigger a massive bipolar outflow from the Herbig Be
component. Based on these conclusions, we speculate that the origin
of the outburst is an event of enhanced mass accretion,
similar to those occuring in EX~Ors and FU~Ors.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astronomy \& Astrophysics Letters}
arXiv:1007.0682
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%%--------SubmissionID=2399----------------
%% Title
{\large\bf{Hydrides in Young Stellar Objects: Radiation tracers in a protostar-disk-outflow system}}
%% Authors
{\bf{ Arnold O. Benz$^{1}$, Simon Bruderer$^{1}$, Ewine F. van Dishoeck$^{2,3}$, WISH team$^{2}$ and HIFI team$^{1}$}}
%% Institutions
$^1$ {Institute of Astronomy, ETH Zurich, Switzerland} \\
$^2$ {Leiden Observatory, Leiden University, Leiden, The Netherlands} \\
$^3$ {Max Planck Institut f\"{u}r Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany}
%% Email
{E-mail contact: benz {\em at} astro.phys.ethz.ch}
%% LATEX COMMANDS
%% Abstract body
{Hydrides of the most abundant heavier elements are fundamental
molecules in cosmic chemistry. Some of them trace gas irradiated by
UV or X-rays.\\
We aim at exploring the abundances of major hydrides in W3 IRS5, a
prototypical region of high-mass star formation.\\
W3 IRS5 was observed by HIFI on the Herschel Space Observatory with
deep integration ($\simeq$ 2500 s) in 8 spectral regions.\\
The target lines including CH, NH, H$_3$O$^+$ and the new molecules
SH$^+$, H$_2$O$^+$, and OH$^+$ are detected. The H$_2$O$^+$ and
OH$^+$ $J=1-0$ lines are found mostly in absorption, but appear to
have also weak emissions (P-Cyg-like). Emissions need high density
and thus originate likely near the protostar. This is corroborated
by the absence of line shifts relative to the young stellar object
(YSO). In addition, H$_2$O$^+$ and OH$^+$ also show strong
absorption components shifted relative to W3 IRS5, which are
attributed to foreground clouds.\\
The molecular column densities derived from observations correlate
well with predictions of a model assuming the main emission region
in outflow walls, heated and irradiated by protostellar UV
radiation.}
% Journal
{ Accepted by Astronomy and Astrophysics Letters}
%% Preprints URL
http://www.exp-astro.phys.ethz.ch/astro1/Users/benz/papers/Hydrides1.pdf
\v5
%%--------SubmissionID=2372----------------
%% Title
{\large\bf{Testing the theory of grain growth and fragmentation by millimeter observations of protoplanetary disks}}
%% Authors
{\bf{ T. Birnstiel$^{1}$, L. Ricci$^{2}$, F. Trotta$^{2,3}$, C.P. Dullemond$^{1}$, A. Natta$^{3}$, L. Testi$^{2,3}$, C. Dominik$^{4,5}$, T. Henning$^{1}$, C.W. Ormel$^{1}$ and A. Zsom$^{1}$}}
%% Institutions
$^1$ {Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, 69117 Heidelberg, Germany} \\
$^2$ {European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany} \\
$^3$ {Osservatorio Astrofisico di Arcetri, INAF, Largo E. Fermi 5, 50125 Firenze, Italy} \\
$^4$ {Astronomical Institute ``Anton Pannekoek'', University of Amsterdam, PO Box 94249, 1090 GE Amsterdam, The Netherlands} \\
$^5$ {Afdeling Sterrenkunde, Radboud Universiteit Nijmegen, Postbus 9010, 6500 GL Nijmegen, The Netherlands}
%% Email
{E-mail contact: birnstiel {\em at} mpia.de}
%% LATEX COMMANDS
%% Abstract body
{\em Context}. Observations at sub-millimeter and mm wavelengths will in
the near future be able to resolve the radial dependence of the mm
spectral slope in circumstellar disks with a resolution of around a
few AU at the distance of the closest star-forming regions. \\
{\em Aim}. We aim to constrain physical models of grain growth and fragmentation by a large sample of (sub-)mm observations of disks around pre-main sequence stars in the Taurus-Auriga and Ophiuchus star-forming regions.\\
{\em Methods}. State-of-the-art coagulation/fragmentation and disk-structure codes are coupled to produce steady-state grain size distributions and to predict the spectral slopes at (sub-)mm wavelengths.\\
{\em Results}. This work presents the first calculations predicting the mm spectral slope based on a physical model of grain growth. Our models can quite naturally reproduce the observed mm-slopes, but a simultaneous match to the observed range of flux levels can only be reached by a reduction of the dust mass by a factor of a few up to about 30 while keeping the gas mass of the disk the same. This dust reduction can either be caused by radial drift at a reduced rate or during an earlier evolutionary time (otherwise the predicted fluxes would become too low) or due to efficient conversion of dust into larger, unseen bodies.
% Journal
{ Accepted by A\&A Letters}
%% Preprints URL
http://adsabs.harvard.edu/abs/2010arXiv1006.0940B
\v5
%%--------SubmissionID=2383----------------
%% Title
{\large\bf{The NH$_2$D/NH$_3$ ratio toward pre-protostellar cores around\\
the UCH~{\small II} region in IRAS\,20293+3952}}
%% Authors
{\bf{ G. Busquet$^{1}$, A. Palau$^{2}$, R. Estalella$^{1}$, J.~M. Girart$^{2}$, \'A. S\'anchez-Monge$^{1}$, S. Viti$^{3}$, P.~T.~P. Ho$^{4,5}$ and Q. Zhang$^{5}$}}
%% Institutions
$^1$ {Departament d'Astronomia i Meteorologia (IEEC-UB), Institut de Ci\`encies del Cosmos, Universitat de Barcelona, Mart\'{\i} i Franqu\`es 1, E-08028 Barcelona, Catalunya, Spain} \\
$^2$ {Institut de Ci\`encies de l'Espai (CSIC-IEEC), Campus UAB, Facultat de Ci\`encies, Torre C-5 parell, E-08193 Bellaterra, Catalunya, Spain} \\
$^3$ {Department of Physics and Astronomy, University College London, Grower Street, London WC1E 6BT, UK} \\
$^4$ {Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, 02138, USA} \\
$^5$ {Academia Sinica Institute of Astronomy and Astrophysics, Taipei, Taiwan}
%% Email
{E-mail contact: gbusquet {\em at} am.ub.es}
%% LATEX COMMANDS
\newcommand{\nhtd} {NH$_2$D}
\newcommand{\nh} {NH$_3$}
\newcommand{\uchii} {UC\ion{H}{ii}}
\newcommand{\dfrac} {$D_{\mathrm{frac}}$}
%% Abstract body
{\em Context}. The deuterium fractionation, $D_{\mathrm{frac}}$, has been proposed as an evolutionary indicator in
pre-protostellar and protostellar cores of low-mass star-forming regions.\\
{\em Aims}. We investigate $D_{\mathrm{frac}}$, with high
angular resolution, in the cluster environment surrounding the UCH~{\small II} region
IRAS\,20293+3952.\\
{\em Methods}. We performed high angular resolution observations with the IRAM Plateau de Bure
Interferometer (PdBI) of the ortho-\nhtd\,$1_{11}$--$1_{01}$ line at 85.926~GHz and compared them with
previously reported VLA NH$_3$ data.\\
{\em Results}. We detected strong NH$_2$D emission toward the pre-protostellar cores
identified in NH$_3$ and dust emission, all located in the vicinity of the UCH~{\small II} region
IRAS\,20293+3952. We found high values of $D_{\mathrm{frac}}\simeq$0.1--0.8 in all the pre-protostellar cores and
low values, $D_{\mathrm{frac}}<0.1$, associated with young stellar objects.\\
{\em Conclusions}. The high values of $D_{\mathrm{frac}}$ in
pre-protostellar cores could be indicative of evolution, although outflow interactions and UV radiation
could also play a role.
% Journal
{ Accepted by Astronomy \& Astrophysics Letters}
%% Preprints URL
http://arxiv.org/abs/1006.4280
\v5
{\large\bf{New Herbig Ae/Be stars confirmed via high-resolution optical spectroscopy.}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ A. Carmona$^1$, M.E. van den Ancker$^2$, M. Audard$^1$, Th. Henning $^3$, J. Setiawan$^3$,\ and J. Rodmann$^4$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {ISDC Data Centre for Astrophysics \& Geneva Observatory, University of Geneva, chemin d'Ecogia 16, 1290 Versoix, Switzerland} \\
$^2$ {European Southern Observatory,
Karl Schwarzschild Str 2 , 85748 Garching bei M\"unchen, Germany} \\
$^3$ {Max-Planck Institute for Astronomy, K\"onigstuhl 17, 69117 Heidelberg, Germany} \\
$^4$ {ESA/ESTEC, Space Environments \& Effects (TEC-EES), 2200 AG Noordwijk, The Netherlands}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: andres.carmona {\em at} unige.ch}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We present FEROS high-resolution (R$\sim$ 45000) optical spectroscopy of 34 Herbig Ae/Be star candidates
with previously unknown or poorly constrained spectral types.
Within the sample, 16 sources are positionally coincident with nearby (d$700$~pc
(Hen~2-80, Hen~3--1121~N\&S, HD 313571, MWC~953, WRAY~15-1435, and Th~17-35)
are inside or close ($<5'$) to regions with extended 8 $\mu$m continuum emission and
in their 20' vicinity have astronomical sources characteristic of SFRs
(e.g., HII regions, molecular clouds,
dark nebulae, masers, young stellar-objects). These 7 sources are likely to be members of SFRs.}
% Here you write which journal accepted your paper, for example:
{ Accepted by A\&A}
%% If preprints are available on the WWW you can give the web
%% direction here.
http://arxiv.org/abs/1004.3386
\v5
%%--------SubmissionID=2389----------------
%% Title
{\large\bf{C{\small I} observations in the CQ\,Tau proto-planetary disk: evidence of a very low gas-to-dust ratio ?}}
%% Authors
{\bf{ Edwige Chapillon$^{1}$, B\'ereng\`ere Parise$^{1}$, St\'ephane Guilloteau$^{2,3}$, Anne Dutrey$^{2,3}$ and Valentine Wakelam$^{2,3}$}}
%% Institutions
$^1$ {Max-Planck-Institut f\"ur Radioastronomie, Auf dem H\"ugel 69, 53121 Bonn, Germany} \\
$^2$ {Universit\'e de Bordeaux, Observatoire Aquitain des Sciences de l'Univers, BP 89, F-33271 Floirac Cedex, France} \\
$^3$ {CNRS, UMR 5804, Laboratoire d'Astrophysique de Bordeaux, BP 89, F-33271 Floirac Cedex, France}
%% Email
{E-mail contact: echapill {\em at} mpifr-bonn.mpg.de}
%% LATEX COMMANDS
\newcommand{\CI}{C{\small I}}
\newcommand{\unzero}{$^{3}P_1 \rightarrow {^{3}P_0}$}
\newcommand{\deuxun}{$^{3}P_2 \rightarrow {^{3}P_1}$}
%% Abstract body
{\textit{Context.} The gas and dust dissipation processes of proto-planetary disks are hardly known. Transition disks between Class II (proto-planetary disks) and Class III (debris disks) remain difficult to detect.\\
\textit{Aims.} We investigate the carbon chemistry of the peculiar CQ\,Tau gas disk. It is likely to be a transition disk because it exhibits weak CO emission with a relatively strong millimeter continuum, indicating that the disk may currently be dissipating its gas content.\\
\textit{Methods.} We used APEX to observe the two \CI\ transitions \unzero\ at 492\,GHz and \deuxun\ at 809\,GHz in the disk orbiting CQ\,Tau. We compare the observations to several chemical model predictions. We focus our study on the influence of the stellar UV radiation shape and gas-to-dust ratio.\\
\textit{Results.} We did not detect the \CI\ lines. However, our upper limits are deep enough to exclude high-\CI\ models. The only available models compatible with our limits imply very low gas-to-dust ratios, of the order of only a few.\\
\textit{Conclusions.} These observations strengthen the hypothesis that CQ\,Tau is likely to be a transition disk and suggest that gas disappears before dust.}
% Journal
{ Accepted by A\&A}
%% Preprints URL
\v5
%%--------SubmissionID=2373----------------
%% Title
{\large\bf{Hydrogen permitted lines in the first near-IR spectra of Th 28 microjet: accretion or ejection tracers?}}
%% Authors
{\bf{ Deirdre Coffey$^{1}$, Francesca Bacciotti$^{2}$, Linda Podio$^{1}$ and Brunella Nisini$^{3}$}}
%% Institutions
$^1$ {The Dublin Institute for Advanced Studies, 31 Fitzwilliam place, Dublin 2, Ireland} \\
$^2$ {Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy} \\
$^3$ {Osservatorio di Roma, Frascati, Roma, Italy}
%% Email
{E-mail contact: dac {\em at} cp.dias.ie}
%% LATEX COMMANDS
%% Abstract body
{We report the first near-infrared detection of the bipolar microjet
from T Tauri star ThA 15-28 (hereafter Th 28). Spectra were obtained
with VLT/ISAAC for the slit both perpendicular and parallel to the
flow to examine jet kinematics and gas physics within the first
arcsecond from the star. The jet was successfully detected in both
molecular and atomic lines. The H$_2$ component was found to be
entirely blueshifted around the base of the bipolar jet. It shows
that only the blue lobe is emitting in H$_2$ while light is
scattered in the direction of the red lobe, highlighting an
asymmetric extinction and/or excitation between the two lobes.
Consistent with this view, the red lobe is brighter in all atomic
lines. Interestingly, the jet was detected not only in [Fe II], but
also in Br$\gamma$ and Pa$\beta$ lines. Though considered tracers
mainly of accretion, we find that these high excitation hydrogen
permitted lines trace the jet as far as 150 AU from the star. This
is confirmed in a number of ways: the presence of the [Fe II] 2.13
micron line which is of similarly high excitation; H I velocities
which match the jet [Fe II] velocities in both the blue and red
lobe; and high electron density close to the source of
$>$6$\times$10$^4$ cm$^{-3}$ derived from the [Fe II] 1.64,1.60
micron ratio. These near-infrared data complement HST/STIS optical
and near-ultraviolet data for the same target which were used in a
jet rotation study, although no rotation signature could be
identified here due to insufficient angular resolution. The
unpublished HST/STIS H$\alpha$ emission is included here along side
the other H I lines. Identifying Br$\gamma$ and Pa$\beta$ as tracers
of ejection is significant because of the importance of finding
strong near-infrared probes close to the star, where forbidden lines
are quenched, which will help understand accretion-ejection when
observed with high spatial resolution instruments such as
VLTI/AMBER.}
% Journal
{ Accepted by The Astrophysical Journal}
%% Preprints URL
http://arxiv.org/abs/1006.5400
\v5
%%--------SubmissionID=2371----------------
%% Title
{\large\bf{Dead zones in protostellar discs: the case of Jet Emitting Discs}}
%% Authors
{\bf{ Celine Combet$^{1}$, Jonathan Ferreira$^{2}$ and Fabien Casse$^{3}$}}
%% Institutions
$^1$ {Dept. of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, United Kingdom} \\
$^2$ {Laboratoire d'Astrophysique de Grenoble, UJF/CNRS, BP 53, 38041 Grenoble Cedex 9, France} \\
$^3$ {Laboratoire APC, Universit´e Paris Diderot, 10, rue A. Domon et L. Duquet 75205, Paris Cedex 13, France}
%% Email
{E-mail contact: celine.combet {\em at} astro.le.ac.uk}
%% LATEX COMMANDS
%% Abstract body
{Planet formation and migration in accretion discs is a very active
topic. Among the many aspects related to that question, dead zones
are of particular importance as they can influence both the
formation and the migration of planetary embryos. The ionisation
level in the disc is the key element in determining the existence
and the location of the dead zone. This has been studied either
within the Standard Accretion Disc (SAD) framework or using
parametric discs. In this paper, we extend this study to the case of
Jet Emitting Discs (JED), the structure of which strongly differ
from SADs because of the new energy balance and angular momentum
extraction imposed by the jets. We make use of the (r, z) density
distributions provided by self-similar accretion-ejection models,
along with the JED thermal structure derived in a previous paper, to
create maps of the ionisation structure of JEDs. We compare the
ionisation rates we obtain to the critical value required to trigger
the magneto-rotational instability.It is found that JEDs have a much
higher ionisation degree than SADs which renders very unlikely the
presence of a dead zone in these discs. As JEDs are believed to
occupy the inner regions of accretion discs, the extension of the
dead zones published in the literature should be re-considered for
systems in which a jet is present. Moreover, since JEDs require
large scale magnetic fields close to equipartition, our findings
raise again the question of magnetic field advection in
circumstellar accretion discs.}
% Journal
{ Accepted by A\&A}
%% Preprints URL
http://arxiv.org/abs/1006.4715
\v5
{\large\bf{Strong accretion on a deuterium-burning brown dwarf}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ F. Comer\'on$^1$, L. Testi$^1$ \ and A. Natta$^2$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {ESO, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei M\"unchen, Germany} \\
$^2$ {Osservatorio Astrofisico di Arcetri, INAF, Largo E. Fermi 5, I-50125 Firenze, Italy}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: fcomeron {\em at} eso.org}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{
{\it Context:}
The accretion processes that accompany the earliest stages of star formation have been shown in recent years to extend to masses well below the substellar limit, and even to masses close to the deuterium-burning limit, suggesting that the features characteristic of the T~Tauri phase are also common to brown dwarfs.\\
{\it Aims:}
We discuss new observations of GY~11, a young brown dwarf in the $\rho$~Ophiuchi embedded cluster.\\
{\it Methods:}
We have obtained for the first time low resolution long-slit spectroscopy of GY~11 in the red visible region, using the FORS1 instrument at the VLT. The spectral region includes accretion diagnostic lines such as H$\alpha$ and the CaII infrared triplet.\\
{\it Results:}
The visible spectrum allows us to confirm that GY~11 lies well below the hydrogen-burning limit, in agreement with earlier findings based on the near-infrared spectral energy distribution. We obtain an improved derivation of its physical parameters, which suggest that GY~11 is on or near the deuterium-burning phase. We estimate a mass of 30~M$_{\rm Jup}$, a luminosity of $6 \times 10^{-3}$~L$_\odot$, and a temperature of 2700~K. We detect strong H$\alpha$ and CaII triplet emission, and we estimate from the latter an accretion rate ${\dot M}_{\rm acc} = 9.5 \times 10^{-10}$~M$_\odot$~yr$^{-1}$, which places GY~11 among the objects with the largest ${\dot M}_{\rm acc} / M_*$ ratios measured thus far in their mass range. This might be an indication that accretion in GY~11 is driven by gravitational instability of its circum(sub-)stellar disk. The intense H$\alpha$ emission is in contrast with the non-detection of Pa$\beta$ and Br$\gamma$ emission reported by Natta et al. (2004), and we discuss possible implications of this on the physical characteristics of the region where hydrogen emission is produced. Using archive near-infrared imaging obtained at different epochs we prove that the H$_2$ emission previously reported in infrared spectra of GY~11 is due to a chance coincidence with Herbig-Haro knots from the nearby source VLA1623, and not to a molecular outflow driven by GY~11. As a byproduct of our observations we also have obtained a spectrum of the neighboring embedded low mass star GY~10, which we classify as M5.5.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astronomy and Astrophysics}
%% If preprints are available on the WWW you can give the web
%% direction here.
{\tt http://www.eso.org/$\sim$fcomeron/GY11.pdf}
\v5
%%--------SubmissionID=2376----------------
%% Title
{\large\bf{The Angular Momentum of Magnetized Molecular Cloud Cores: a 2D-3D comparison}}
%% Authors
{\bf{ Sami Dib$^{1,2}$, Patrick Hennebelle$^{3}$, Jaime E. Pineda$^{4}$, Timea Csengeri$^{1}$, Sylvain Bontemps$^{5}$, Edouard Audit$^{1}$ and Alyssa A. Goodman$^{4, 6}$}}
%% Institutions
$^1$ {Service d'Astrophysique, DSM/Irfu, CEA/Saclay, F-91191, Gif-sur-Yvette Cedex, France} \\
$^2$ {Astronomical Institute, University of Utrecht, Princetonplein 5, 3584 CC, Utrecht, The Netherlands} \\
$^3$ {Laboratoire de Radioastronomie, UMR CNRS 8112, ´ Ecole Normale Sup´erieure, Observatoire de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France} \\
$^4$ {Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA} \\
$^5$ {CNRS/INU, Laboratoire d'Astrophysique de Bordeaux, UMR 5804, BP 89, 33271, Floirac, Cedex, France}\\
$^6$ {Initiative for Innovative Computing, Harvard University, 60 Oxford Street, Cambridge, MA 02138, USA}
%% Email
{E-mail contact: sami.dib {\em at} cea.fr}
%% LATEX COMMANDS
%% Abstract body
{In this work, we present a detailed study of the rotational
properties of magnetized and self-gravitating dense molecular cloud
cores formed in a set of two very high resolution three-dimensional
molecular cloud simulations with decaying turbulence. The
simulations have been performed using the adaptative mesh refinement
code RAMSES with an effective resolution of 4096$^3$ grid cells. One
simulation represents a mildly magnetically-supercritical cloud and
the other a strongly magnetically-supercritical cloud. We identify
dense cores at a number of selected epochs in the simulations at two
density thresholds which roughly mimick the excitation densities of
the NH$_{3}$ ($J-K$)=(1,1) transition and the N$_{2}$H$^{+}$ (1-0)
emission line. A noticeable global difference between the two
simulations is the core formation efficiency (CFE) of the high
density cores. In the strongly supercritical simulations the CFE is
$~33$ percent per unit free-fall time of the cloud ($t_{ff,cl}$),
whereas in the mildly supercritical simulations this value goes down
to $\sim 6$ percent per unit $t_{ff,cl}$. A comparison of the
intrinsic specific angular momentum ($j_{3D}$) distributions of the
cores with the specific angular momentum derived using synthetic
two-dimensional velocity maps of the cores ($j_{2D}$), shows that
the synthetic observations tend to overestimate the true value of
the specific angular momentum by a factor of $\sim 8-10$. We find
that the distribution of the ratio $j_{3D}/j_{2D}$ of the cores
peaks at around $\sim 0.1$. The origin of this discrepancy lies in
the fact that contrary to the intrinsic determination of $j$ which
sums up the individual gas parcels contributions to the angular
momentum, the determination of the specific angular momentum using
the standard observational procedure which is based on a measurement
on the global velocity gradient under the hypothesis of uniform
rotation smoothes out the complex fluctuations present in the
three-dimensional velocity field. Our results may well provide a
natural explanation for the discrepancy by a factor $\sim 10$
observed between the intrinsic three-dimensional distributions of
the specific angular momentum and the corresponding distributions
derived in real observations. We suggest that previous and future
measurements of the specific angular momentum of dense cores which
are based on the measurement of the observed global velocity
gradients may need to be reduced by a factor of $\sim 10$ in order
to derive a more accurate estimate of the true specific angular
momentum in the cores. We also show that the exponent of the
size-specific angular momentum relation are smaller ($\sim 1.4$) in
the synthetic observations than their values derived in the
three-dimensional space ($\sim 1.8$).}
% Journal
{ Accepted by Astrophysical Journal}
%% Preprints URL
http://arxiv.org/abs/1003.5118
\v5
%%--------SubmissionID=2374----------------
%% Title
{\large\bf{The physical and dynamical structure of Serpens: Two very different sub-(proto)clusters}}
%% Authors
{\bf{ A. Duarte-Cabral$^{1}$, G. A. Fuller$^{1}$, N. Peretto$^{1}$, J. Hatchell$^{2}$, E. F. Ladd$^{3}$, J. Buckle$^{4, 5}$, J. Richer$^{4, 5}$ and S. F. Graves$^{4, 5}$}}
%% Institutions
$^1$ {Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, U.K.} \\
$^2$ {School of Physics, University of Exeter, Exeter EX4 4QL, U.K.} \\
$^3$ {Department of Physics, Bucknell University, Lewisburg, PA 17837, U.S.A.} \\
$^4$ {Astrophysics Group, Cavendish Laboratory, J J Thomson Avenue, Cambridge, CB3 0HE, U.K.} \\
$^5$ {Kavli Institute for Cosmology, c/o Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, U.K.}
%% Email
{E-mail contact: Ana.Cabral {\em at} postgrad.manchester.ac.uk}
%% LATEX COMMANDS
%% Abstract body
{The Serpens North Cluster is a nearby low mass star forming region
which is part of the Gould Belt. It contains a range of young stars
thought to correspond to two different bursts of star formation and
provides the opportunity to study different stages of cluster
formation. This work aims to study the molecular gas in the Serpens
North Cluster to probe the origin of the most recent burst of star
formation in Serpens. Transitions of the C$^{17}$O and C$^{18}$O
observed with the IRAM 30m telescope and JCMT are used to study the
mass and velocity structure of the region while the physical
properties of the gas are derived using LTE and non-LTE analyses of
the three lowest transitions of C$^{18}$O. The molecular emission
traces the two centres of star formation which are seen in
submillimetre dust continuum emission. In the $\sim$40~M$_\odot$ NW
sub-cluster the gas and dust emission trace the same structures
although there is evidence of some depletion of the gas phase
C$^{18}$O. The gas has a very uniform temperature ($\sim$10~K) and
velocity ($\sim$8.5~km/s) throughout the region. This is in marked
contrast to the SE sub-cluster. In this region the dust and the gas
trace different features, with the temperature peaking between the
submillimetre continuum sources, reaching up to $\sim$14~K. The gas
in this region has double peaked line profiles which reveal the
presence of a second cloud in the line of sight. The submillimetre
dust continuum sources predominantly appear located in the interface
region between the two clouds. Even though they are at a similar
stage of evolution, the two Serpens sub-clusters have very different
characteristics. We propose that these differences are linked to the
initial trigger of the collapse in the regions and suggest that a
cloud-cloud collision could explain the observed properties.}
% Journal
{ Accepted by A\&A}
%% Preprints URL
http://arxiv.org/abs/1006.0879
\v5
%%--------SubmissionID=2391----------------
%% Title
{\large\bf{Modeling Mid-Infrared Variability of Circumstellar Disks with Non-Axisymmetric Structure}}
%% Authors
{\bf{ Kevin Flaherty$^{1}$ and James Muzerolle$^{1,2}$}}
%% Institutions
$^1$ {Steward Observatory, University of Arizona} \\
$^2$ {Space Telescope Science Institute}
%% Email
{E-mail contact: kflaherty {\em at} as.arizona.edu}
%% LATEX COMMANDS
%% Abstract body
{Recent mid-infrared observations of young stellar objects have found
significant variations possibly indicative of changes in the
structure of the circumstellar disk. Previous models of this
variability have been restricted to axisymmetric perturbations in
the disk. We consider simple models of a non-axisymmetric variation
in the inner disk, such as a warp or a spiral wave. We find that the
precession of these non-axisymmetric structures produce negligible
flux variations but a change in the height of these structures can
lead to significant changes in the mid-infrared flux. Applying these
models to observations of the young stellar object LRLL 31 suggests
that the observed variability could be explained by a warped inner
disk with variable scale height. This suggests that some of the
variability observed in young stellar objects could be explained by
non-axisymmetric disturbances in the inner disk and this variability
would be easily observable in future studies.}
% Journal
{ Accepted by ApJ}
%% Preprints URL
http://arxiv.org/abs/1007.1249
\clearpage
%% Between these brackets you write the title of your paper:
{\large\bf{Infall, outflow, and rotation in the G19.61-0.23 hot molecular core}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{R. S. Furuya$^1$, R. Cesaroni$^2$, \ and H. Shinnaga$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI\,96720, U.S.A.} \\
$^2$ {INAF-Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze, Italy} \\
$^3$ {Caltech Submillimeter Observatory, California Institute of Technology,
111 Nowelo Street, Hilo, HI\,96720, U.S.A.}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: {\texttt rsf {\em at} subaru.naoj.org}}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{\emph{Aims.}~
The main goal of this study is to perform a sub-arcsecond resolution
analysis
of the high-mass star formation region G\,19.61-0.23, both in the continuum and
molecular line emission. While the centimeter continuum images will be
discussed in detail in a forthcoming paper, here we focus on the (sub)mm
emission, devoting special attention to the hot molecular core.\\
\emph{Methods.}
A set of multi-wavelength continuum and molecular line emission data
between 6\,cm and 890 $\mu$m were taken with the Very Large Array (VLA),
Nobeyama Millimeter Array (NMA),
Owens Valley Radio Observatory (OVRO), and
Submillimeter Array (SMA).
These data were analyzed in conjuction with previously published data.\\
\emph{Results.}
Our observations resolve the HMC into three cores
whose masses are on the order of $10^1-10^3$~$M_\odot$.
No submm core presents detectable free-free emission in the centimeter regime,
but they appear to be associated with masers and thermal line emission
from complex organic molecules.
Towards the most massive core, SMA1, the CH$_3$CN ($18_K-17_K$) lines
reveal hints of rotation
about the axis of a jet/outflow traced by H$_2$O maser
and H$^{13}$CO$^+$ (1--0) line emission.
Inverse P-Cygni profiles of the $^{13}$CO (3--2) and C$^{18}$O (3--2) lines seen towards
SMA1 indicate that the
central high-mass (proto)star(s) is (are) still gaining
mass with an accretion rate
$\ge 3 ~10^{-3}$ $M_\odot$ yr$^{-1}$.
Due to the linear scales and the large values of the accretion rate, we
hypothesize that we are observing an
accretion flow towards a cluster in the making,
rather than towards a single massive star.
}
% Here you write which journal accepted your paper, for example:
{Accepted by A\&A}
%% If preprints are available on the WWW you can give the web
%% direction here.
Preprint with full-resolution figures is available at
\texttt{http://subarutelescope.org/staff/rsf/publication.html}
\v5
%%--------SubmissionID=2375----------------
%% Title
{\large\bf{Pre-main sequence stars with disks in the Eagle Nebula observed in scattered light}}
%% Authors
{\bf{ M. G. Guarcello$^{1,2,3}$, F. Damiani$^{2}$, G. Micela$^{2}$, G. Peres$^{1}$, L. Prisinzano$^{2}$ and S. Sciortino$^{2}$}}
%% Institutions
$^1$ {Dipart. di Scienze Fisiche ed Astronomiche, Universit´ di Palermo, Piazza del Parlamento 1, I-90134 Palermo Italy} \\
$^2$ {INAF - Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo Italy} \\
$^3$ {Currently at Smithsonian Astrophysical Observatory, MS-3, 60 Garden Street, Cambridge, MA 02138, USA}
%% Email
{E-mail contact: mguarcel {\em at} head.cfa.harvard.edu}
%% LATEX COMMANDS
%% Abstract body
{NGC~6611 and its parental cloud, the Eagle Nebula (M16), are
well-studied star-forming regions, thanks to their large content of
both OB stars and stars with disks and the observed ongoing star
formation. In our previous studies of the Eagle Nebula, we
identified 834 disk-bearing stars associated with the cloud, after
detecting their excesses in NIR bands from $J$ band to 8.0$\mu m$.
In this paper, we study in detail the nature of a subsample of
disk-bearing stars that show peculiar characteristics. They appear
older than the other members in the $V$ vs. $V-I$ diagram, and/or
they have one or more IRAC colors at pure photospheric values,
despite showing NIR excesses, when optical and infrared colors are
compared. We confirm the membership of these stars to M16 by a
spectroscopic analysis. The physical properties of these stars with
disks are studied by comparing their spectral energy distributions
(SEDs) with the SEDs predicted by models of T-Tauri stars with disks
and envelopes. We show that the age of these stars estimated from
the $V$ vs. $V-I$ diagram is unreliable since their $V-I$ colors are
altered by the light scattered by the disk into the line of sight.
Only in a few cases their SEDs are compatible with models with
excesses in $V$ band caused by optical veiling. Candidate members
with disks and photospheric IRAC colors are selected by the used NIR
disk diagnostic, which is sensitive to moderate excesses, such as
those produced by disks with low masses. In 1/3 of these cases,
scattering of stellar flux by the disks can also be invoked. The
photospheric light scattered by the disk grains into the line of
sight can affect the derivation of physical parameters of Class~II
stars from photometric optical and NIR data. Besides, the disks
diagnostic we defined are useful for selecting stars with disks,
even those with moderate excesses or whose optical colors are
altered by veiling or photospheric scattered light.}
% Journal
{ Accepted by Astronomy and Astrophysics}
%% Preprints URL
http://www.astropa.unipa.it/ mguarce/6611\_scatter.ps
\v5
%%--------SubmissionID=2382----------------
%% Title
{\large\bf{Spitzer Observations of IC 2118}}
%% Authors
{\bf{ S. Guieu$^{1}$, L. M. Rebull$^{1}$, J. R. Stauffer$^{1}$, F. J. Vrba$^{2}$, A. Noriega-Crespo$^{1}$, T. Spuck$^{3}$, T. Rolofsen Moody$^{4}$, B. Sepulveda$^{5}$, C. Weehler$^{6}$, A. Maranto$^{7}$, D. M. Cole$^{1}$, N. Flagey$^{1}$, R. Laher$^{1}$, B. Penprase$^{8}$, S. Ramirez$^{9}$ and S. Stolovy$^{1}$}}
%% Institutions
$^1$ {SSC} \\
$^2$ {USNO/Flagstaff} \\
$^3$ {OCHS} \\
$^4$ {NJAC} \\
$^5$ {LHS} \\
$^6$ {LBHS} \\
$^7$ {McDonogh}\\
$^8$ {Pomona} \\
$^9$ {IPAC}
%% Email
{E-mail contact: sguieu {\em at} eso.org}
%% LATEX COMMANDS
%% Abstract body
{IC 2118, also known as the Witch Head Nebula, is a wispy, roughly
cometary, $\sim$5 degree long reflection nebula, and is thought to
be a site of triggered star formation. In order to search for new
young stellar objects (YSOs), we have observed this region in 7 mid-
and far-infrared bands using the Spitzer Space Telescope and in 4
bands in the optical using the U. S. Naval Observatory 40-inch
telescope. We find infrared excesses in 4 of the 6 previously-known
T Tauri stars in our combined infrared maps, and we find 6 entirely
new candidate YSOs, one of which may be an edge-on disk. Most of the
YSOs seen in the infrared are Class II objects, and they are all in
the "head" of the nebula, within the most massive molecular cloud of
the region.}
% Journal
{ Accepted by ApJ}
%% Preprints URL
http://arxiv.org/abs/1007.0241
\v5
%%--------SubmissionID=2396----------------
%% Title
{\large\bf{Star formation in Cometary globule 1: the second generation}}
%% Authors
{\bf{ L. K. Haikala$^{1,2}$, M. M. M\"akel\"a$^{1,2}$ and P. V\"ais\"anen$^{3,4}$}}
%% Institutions
$^1$ {Observatory, University of Helsinki, Finland} \\
$^2$ {Department of Physics, University of Helsinki, Finland} \\
$^3$ {South African Astronomical Observatory, Cape Town, South Africa} \\
$^4$ {Southern African Large Telescope Foundation, Cape Town, South Africa}
%% Email
{E-mail contact: lauri.haikala {\em at} helsinki.fi}
%% LATEX COMMANDS
%% Abstract body
{{\em Context}. Cometary Globule 1 (CG~1) is the archetype cometary globule in the Gum nebula. \\
{\em Aims}. To discover the stars possibly embedded
in the globule head and to map the distribution of ISM in it. \\
{\em Methods}. { C$^{18}$O spectral line observations, NIR spectrosopy, narrow and
broad band NIR imaging and stellar photometry are used to analyse
the structure of CG~1 head and the extinction of stars in its
direction.} \\
{\em Results}. { A young stellar object (YSO) associated with a bright NIR
nebulosity and a molecular hydrogen object (MHO 1411, a probable
obscured HH-object), were discovered in the globule. Molecular
hydrogen and Br$\gamma$ \ line emission is seen in the direction
of the YSO. The YSO is a Class II candidate. The observed
maximum optical extinction in the globule head is 9.2
magnitudes. The peak N(H$_2$) \ column density and the total mass
derived from the extinction are 9.0 10$^{21}$cm$^{-2}$ and 16.7
M$_{\odot}$ (d/300pc)$^2$. C$^{18}$O emission in the
globule head is detected in a 4' by 1'5 area with a
sharp maximum SW of the YSO. Three regions (C$^{18}$O\_SE,
C$^{18}$O\_max and C$^{18}$O\_NW) can be
discerned in C$^{18}$O line velocity and excitation
temperature. C$^{18}$O\_SE coincides with a strong NIR
surface brightness below the bright HAeBe star NX Pup and
C$^{18}$O\_NW with the optical extinction maximum.
Because of variations in the C$^{18}$O excitation
temperature the integrated C$^{18}$O line emission does
not follow the optical extinction. It is argued that the
C$^{18}$O excitation temperatures in
C$^{18}$O\_SE and C$^{18}$O\_max is higher than
in C$^{18}$O\_NW because of radiative heating by NX Pup
(C$^{18}$O\_SE) and interaction of the YSO with the parent
cloud (C$^{18}$O\_max). No indication other than the
molecular hydrogen emission and the molecular hydrogen object of
a strong molecular outflow from the YSO is evident. The IRAS
point source 07178--4429 located in the CG~1 head resolves into
two sources in the HIRES enhanced IRAS images. The 12 and
25 micron emission originates mainly in the star NX Puppis
and the 60 and 100 micron emission in the YSO. The IRAS FIR
luminosity of the YSO is 3.1 $L_{\odot}$.}}
% Journal
{ Accepted by Astronomy and Astrophysics}
%% Preprints URL
http://arxiv.org/abs/1007.2087
\vspace{0.3cm}
%%--------SubmissionID=2400----------------
%% Title
{\large\bf{A Methane Imaging Survey for T Dwarf Candidates in Rho Ophiuchi}}
%% Authors
{\bf{ Karl E. Haisch Jr.$^{1}$, Mary Barsony$^{2}$ and Chris Tinney$^{3}$}}
%% Institutions
$^1$ {Utah Valley University} \\
$^2$ {Space Science Institute} \\
$^3$ {University of New South Wales}
%% Email
{E-mail contact: Karl.Haisch {\em at} uvu.edu}
%% LATEX COMMANDS
%% Abstract body
{We report the results of the first deep, wide-field, near-infrared
methane imaging survey of the $\rho$ Ophiuchi cloud core to search
for T dwarfs. Among the 6587 objects detected, 22 were identified as
T dwarf candidates. Brown dwarf models indicate that at the age and
distance of the $\rho$ Ophiuchi cloud, these T dwarf candidates have
masses between 1 and 2 Jupiter masses. If confirmed as genuine T
dwarfs, these objects would be the youngest, lowest mass, and lowest
gravity free-floating objects ever directly observed. The existence
of these candidates suggests that the initial mass function of the
$\rho$ Ophiuchi cloud extends well into the regime of planetary mass
objects. A large fraction (59\% $\pm$ 16\%) of our T dwarf
candidates appear to be surrounded by circumstellar disks, and thus
represent the lowest mass objects yet found to harbor circumstellar
disks.}
% Journal
{ Accepted by ApJ Letters}
%% Preprints URL
http://arxiv.org/abs/1007.2406
\vspace{0.3cm}
%%--------SubmissionID=2377----------------
%% Title
{\large\bf{Vortices as Nurseries for Planetesimal Formation in Protoplanetary Discs}}
%% Authors
{\bf{ Kevin Heng$^{1}$ and Scott J. Kenyon$^{2}$}}
%% Institutions
$^1$ {Institute for Advanced Study (Princeton) and ETH Zurich} \\
$^2$ {Harvard-Smithsonian Center for Astrophysics}
%% Email
{E-mail contact: heng {\em at} ias.edu}
%% LATEX COMMANDS
%% Abstract body
{Turbulent, two-dimensional, hydrodynamic flows are characterized by
the emergence of coherent, long-lived vortices without a need to
invoke special initial conditions. Vortices have the ability to
sequester particles, with typical radii from about 1 mm to 10 cm,
that are slightly decoupled from the gas. A generic feature of discs
with surface density and effective temperature profiles that are
decreasing, power-law functions of radial distance is that four
vortex zones exist for a fixed particle size. In particular, two of
the zones form an annulus at intermediate radial distances within
which small particles reside. Particle capture by vortices occurs on
a dynamical time scale near and at the boundaries of this annulus.
As the disc ages and the particles grow via coagulation, the size of
the annulus shrinks. Older discs prefer to capture smaller particles
because the gas surface density decreases with time, a phenomenon we
term ?vortex aging?. More viscous, more dust-opaque and/or less
massive discs can have vortices that age faster and trap a broader
range of particle sizes throughout the lifetime of the disc. Thus,
how efficiently a disc retains its mass in solids depends on the
relative time scales between coagulation and vortex aging. If
vortices form in protoplanetary discs, they are important in discs
with typical masses and for particles that are likely to condense
out of the protostellar nebula. Particle capture also occurs at
distances relevant to planet formation. Future infrared,
submillimetre and centimetre observations of grain opacity as a
function of radial distance will test the hypothesis that vortices
serve as nurseries for particle growth in protoplanetary discs.}
% Journal
{ Accepted by MNRAS}
%% Preprints URL
http://arxiv.org/abs/1005.1660
\vspace{0.3cm}
%%--------SubmissionID=2378----------------
%% Title
{\large\bf{Long-Lived Planetesimal Discs}}
%% Authors
{\bf{ Kevin Heng$^{1}$ and Scott Tremaine$^{1}$}}
%% Institutions
$^1$ {Institute for Advanced Study (Princeton)}
%% Email
{E-mail contact: heng {\em at} ias.edu}
%% LATEX COMMANDS
%% Abstract body
{We investigate the survival of planetesimal discs over Gyr
time-scales, using a unified approach that is applicable to all
Keplerian discs of solid bodies: dust grains, asteroids, planets,
etc. Planetesimal discs can be characterized locally by four
parameters: surface density, semimajor axis, planetesimal size and
planetesimal radial velocity dispersion. Any planetesimal disc must
have survived all dynamical processes, including gravitational
instability, dynamical chaos, gravitational scattering, physical
collisions, and radiation forces, that would lead to significant
evolution over its lifetime. These processes lead to a rich set of
constraints that strongly restrict the possible properties of
long-lived discs. Within this framework, we also discuss the
detection of planetesimal discs using radial velocity measurements,
transits, microlensing and the infrared emission from the
planetesimals themselves or from dust generated by planetesimal
collisions.}
% Journal
{ Accepted by MNRAS}
%% Preprints URL
http://adsabs.harvard.edu/abs/2010MNRAS.401..867H
\v5
%%--------SubmissionID=2394----------------
%% Title
{\large\bf{Observational Determination of the Turbulent Ambipolar Diffusion Scale and Magnetic Field Strength in Molecular Clouds}}
%% Authors
{\bf{ Talayeh Hezareh$^{1}$, Martin Houde$^{1}$, Carolyn McCoey$^{2}$ and Hua-bai Li$^{3}$}}
%% Institutions
$^1$ {The University of Western Ontario} \\
$^2$ {University of Waterloo} \\
$^3$ {Max-Planck-Institut fuer Astronomie}
%% Email
{E-mail contact: thezareh {\em at} uwo.ca}
%% LATEX COMMANDS
%% Abstract body
{We study the correlation of the velocity dispersion of the coexisting
molecules $\mathrm{H^{13}CN}$ and $\mathrm{H^{13}CO^{+}}$ and the
turbulent energy dissipation scale in the DR21(OH) star-forming
region. The down-shift of the $\mathrm{H^{13}CO^{+}}$ spectrum
relative to $\mathrm{H^{13}CN}$ is consistent with the presence of
ambipolar diffusion at dissipation length scales that helps the
process of turbulent energy dissipation, but at a different cut-off
for ions compared to the neutrals. We use our observational data to
calculate a turbulent ambipolar diffusion length scale
$L^{'}\simeq17$ mpc and a strength of B$_{\mathrm{pos}}\simeq1.7$ mG
for the plane of the sky component of the magnetic field in
DR21(OH).}
% Journal
{ Accepted by Astrophysical Journal}
%% Preprints URL
\v5
%%--------SubmissionID=2384----------------
%% Title
{\large\bf{Depletion of CCS in a Candidate Warm-Carbon-Chain-Chemistry Source L483}}
%% Authors
{\bf{ Tomoya Hirota$^{1}$, Nami Sakai$^{2}$ and Satoshi Yamamoto$^{2}$}}
%% Institutions
$^1$ {National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan} \\
$^2$ {Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan}
%% Email
{E-mail contact: tomoya.hirota {\em at} nao.ac.jp}
%% LATEX COMMANDS
%% Abstract body
{We have carried out an observation of the CCS
($J_{N}$=2$_{1}$-1$_{0}$) line with the VLA in its D-configuration
toward a protostellar core L483 (IRAS~18140-0440). This is a
candidate source of the newly found carbon-chain rich environment
called "Warm-Carbon-Chain-Chemistry (WCCC)", according to the
previous observations of carbon-chain molecules. The CCS
distribution in L483 is found to consist of two clumps aligned in
the northwest-southeast direction, well tracing the CCS ridge
observed with the single-dish radio telescope. The most remarkable
feature is that CCS is depleted at the core center. Such a CCS
distribution with the central hole is consistent with those of
previously observed prestellar and protostellar cores, but it is
rather unexpected for L483. This is because the distribution of CS,
which is usually similar to that of CCS, is centrally peaked. Our
results imply that the CCS ($J_{N}$=2$_{1}$-1$_{0}$) line would
selectively trace the outer cold envelope in the chemically less
evolved phase that is seriously resolved out with the
interferometric observation. Thus, it is most likely that the high
abundance of CCS in L483 relative to the other WCCC sources is not
due to the activity of the protostar, although it would be related
to its younger chemical evolutionary stage, or a short timescale of
the prestellar phase.}
% Journal
{ Accepted by ApJ}
%% Preprints URL
http://arxiv.org/abs/1007.1066
\clearpage
%%--------SubmissionID=2397----------------
%% Title
{\large\bf{Emergence of Protoplanetary Disks and Successive Formation of Gaseous Planets by Gravitational Instability}}
%% Authors
{\bf{ Shu-ichiro Inutsuka$^{1}$, Masahiro N. Machida$^{2}$ and Tomoaki Matsumoto$^{3}$}}
%% Institutions
$^1$ {Department of Physics, Nagoya University} \\
$^2$ {National Astronomical Observatory} \\
$^3$ {Faculty of Humanity and Environment, Hosei University}
%% Email
{E-mail contact: inutsuka {\em at} nagoya-u.jp}
%% LATEX COMMANDS
%% Abstract body
{We use resistive magnetohydrodynamical (MHD) simulations with the
nested grid technique to study the formation of protoplanetary disks
around protostars from molecular cloud cores that provide the
realistic environments for planet formation. We find that gaseous
planetary-mass objects are formed in the early evolutionary phase by
gravitational instability in regions that are decoupled from the
magnetic field and surrounded by the injection points of the MHD
outflows during the formation phase of protoplanetary disks.
Magnetic decoupling enables massive disks to form and these are
subject to gravitational instability, even at ~10 AU. The frequent
formation of planetary-mass objects in the disk suggests the
possibility of constructing a hybrid planet formation scenario,
where the rocky planets form later under the influence of the giant
planets in the protoplanetary disk.}
% Journal
{ Accepted by The Astrophysical Journal Letters (Vol.718, L58-L62)}
%% Preprints URL
http://arxiv.org/abs/0912.5439
\v5
%%--------SubmissionID=2370----------------
%% Title
{\large\bf{The Directly Imaged Planet around the Young Solar Analog 1RXS~J160929.1-210524: Confirmation of Common Proper Motion, Temperature and Mass}}
%% Authors
{\bf{ David Lafreni\`ere$^{1,2}$, Ray Jayawardhana$^{2}$ and Marten H. van Kerkwijk$^{2}$}}
%% Institutions
$^1$ {D\'epartement de physique, Universit\'e de Montr\'eal, C.P. 6128 Succ. Centre-Ville, Montr\'eal, QC, H3C 3J7, Canada} \\
$^2$ {Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4, Canada}
%% Email
{E-mail contact: david {\em at} astro.umontreal.ca}
%% LATEX COMMANDS
\newcommand{\msun}{\ensuremath{M_{\odot}}}
\newcommand{\mjup}{\ensuremath{M_{\rm Jup}}}
\newcommand\planethost{1RXS~J160929.1-210524}
\newcommand\primary{1RXS~J1609-2105}
\newcommand\companion{1RXS~J1609-2105~b}
%% Abstract body
{Giant planets are usually thought to form within a few tens of AU of
their host stars, and hence it came as a surprise when we found what
appeared to be a planetary mass ($\sim$ 0.008 $\msun$) companion
around the 5 Myr-old solar mass star \planethost\ in the Upper
Scorpius association. At the time, we took the object's membership
in Upper Scorpius ---established from near-infrared, $H$- and
$K$-band spectroscopy--- and its proximity (2.2~arcsec, or 330~AU)
to the primary as strong evidence for companionship, but could not
verify their common proper motion. Here, we present follow-up
astrometric measurements that confirm that the companion is indeed
co-moving with the primary star, which we interpret as evidence that
it is a truly bound planetary mass companion. We also present new
$J$-band spectroscopy and 3.0-3.8~$\mu$m photometry of the
companion. Based on a comparison with model spectra, these new
measurements are consistent with the previous estimate of the
companion effective temperature of $1800\pm200$~K. We present a new
estimate of the companion mass based on evolution models and the
calculated bolometric luminosity of the companion; we obtain a value
of $0.008_{-0.002}^{+0.003}$~M$_\odot$, again consistent with our
previous result. Finally, we present angular differential imaging
observations of the system allowing us to rule out additional
planets in the system more massive than 1~\mjup, 2~\mjup\ and
8~\mjup\ at projected separations larger than 3~arcsec
($\sim$440~AU), 0.7~arcsec ($\sim$100~AU) and 0.35~arcsec
($\sim$50~AU), respectively. This companion is the least massive
known to date at such a large orbital distance; it shows that
objects in the planetary mass range exist at orbital separations of
several hundred AU, posing a serious challenge for current formation
models.}
% Journal
{ Accepted by The Astrophysical Journal}
%% Preprints URL
http://arxiv.org/abs/1006.3070
\v5
%%--------SubmissionID=2395----------------
%% Title
{\large\bf{c2d Spitzer IRS spectra of embedded low-mass young stars: gas-phase emission lines}}
%% Authors
{\bf{ Fred Lahuis$^{1,2}$, Ewine F. van Dishoeck$^{2,3}$, Jes K. J{\o}rgensen$^{4}$, Geoffrey A. Blake$^{5}$ and Neal~J.~Evans~II$^{6}$}}
%% Institutions
$^1$ {SRON Netherlands Institute for Space Research,P.O. Box 800, 9700 AV Groningen, The Netherlands} \\
$^2$ {Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, The Netherlands} \\
$^3$ {Max-Planck-Institut f\"ur extraterrestrische Physik (MPE), Giessenbachstraat 1, 85748 Garching, Germany} \\
$^4$ {Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, {\O}ster Voldgade 5-7, DK-1350 Copenhagen K, Denmark} \\
$^5$ {Division of Geological and Planetary Sciences 150-21, California Institute of Technology, Pasadena, CA 91125, USA} \\
$^6$ {The University of Texas at Austin, Dept. of Astronomy, 1 University Station C1400, Austin, Texas 78712--0259, USA}
%% Email
{E-mail contact: F.Lahuis {\em at} sron.nl}
%% LATEX COMMANDS
\newcommand{\htwo}{H$_2$}
\newcommand{\water}{H$_2$O}
\newcommand{\micron}{$\mu$m}
\newcommand{\spitzer}{\textit{Spitzer}}
\newcommand{\tex}{$T_\mathrm{ex}$}
\newcommand{\neii}{[Ne\,{\sc ii}]}
\newcommand{\neiii}{[Ne\,{\sc iii}]}
\newcommand{\niii}{[Ni\,{\sc ii}]}
\newcommand{\feii}{[Fe\,{\sc ii}]}
\newcommand{\silii}{[Si\,{\sc ii}]}
\newcommand{\si}{[S\,{\sc i}]}
\newcommand{\oi}{[O\,{\sc i}]}
\newcommand{\cii}{[C\,{\sc ii}]}
\newcommand{\siii}{[S\,{\sc iii}]}
\newcommand{\fei}{[Fe\,{\sc i}]}
\newcommand{\cli}{[Cl\,{\sc i}]}
%% Abstract body
{A survey of mid-infrared gas-phase emission lines of \htwo, \water{} and various atoms toward a sample of 43 embedded low-mass young stars in nearby star-forming regions is presented. The sources are selected from the \spitzer{} "Cores to Disks" (c2d) legacy program. \\
{\em Aims}: The environment of embedded protostars is complex both in its physical structure (envelopes, outflows, jets, protostellar disks) and the physical processes (accretion, irradiation by UV and/or X-rays, excitation through slow and fast shocks) which take place. The mid-IR spectral range hosts a suite of diagnostic lines which can distinguish them. A key point is to spatially resolve the emission in the \spitzer-IRS spectra to separate extended PDR and shock emission from compact source emission associated with the circumstellar disk and jets.\\
{\em Methods}: An optimal extraction method is used to separate both spatially unresolved (compact, up to a few hundred AU) and spatially resolved (extended, thousand AU or more) emission from the IRS spectra. The results are compared with the c2d disk sample and literature PDR and shock models to address the physical nature of the sources.\\
{\em Results}: Both compact and extended emission features are observed. Warm (\tex\,few hundred\,K) \htwo, observed through the pure rotational \htwo{} S(0), S(1) and S(2) lines, and \si{} 25 $\mu$m emission is observed primarily in the extended component. \si{} is observed uniquely toward truly embedded sources and not toward disks. On the other hand hot (\tex\,$\gtrsim700$\,K) \htwo, observed primarily through the S(4) line, and \neii{} emission is seen mostly in the spatially unresolved component. \feii{} and \silii{} lines are observed in both spatial components. Hot \water{} emission is found in the spatially unresolved component of some sources.\\
{\em Conclusions}: The observed emission on $\geq$1000 AU scales is characteristic of PDR emission and likely originates in the outflow cavities in the remnant envelope created by the stellar wind and jets from the embedded young stars. Weak shocks along the outflow wall can also contribute. The compact emission is likely of mixed origin, comprised of optically thick circumstellar disk and/or jet/out flow emission from the protostellar object.}
% Journal
{ Accepted by A\&A}
%% Preprints URL
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Sub-Alfv\'enic Non-Ideal MHD Turbulence Simulations with Ambipolar Diffusion: II. Comparison with Observation, Clump Properties, and Scaling to Physical Units}}
%% Here comes the author(s) of the paper, please indicate within $^...$ %% the number which corresponds to the institute of each author.
{\bf{ Christopher F. McKee$^1$, Pak Shing Li$^2$ \ and Richard I. Klein$^3$ }}
%% Here you write your institute name(s) and address(es), %% the number in $^..$ indicates your author number, for example:
$^1$ {Physics Department and Astronomy Department, University of California, Berkeley, CA 94720, USA; and Laboratoire d'Etudes du Rayonnement et de la Mati\`ereen Astrophysique, LERMA-LRA, Ecole Normale Superieure, 24 rue Lhomond, 75005 Paris, France} \\
$^2$ {Astronomy Department, University of California, Berkeley, CA 94720, USA} \\
$^3$ {Astronomy Department, University of California, Berkeley, CA 94720, USA; and Lawrence Livermore National Laboratory, P.O.Box 808, L-23, Livermore, CA 94550, USA}
%% Here you may write the e-mail address of one or more of the authors %% who will act as contact person for preprint requests etc, for example:
{E-mail contact: cmckee {\em at} astro.berkeley.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{Ambipolar diffusion is important in redistributing magnetic flux and in damping Alfv$\acute{e}$n waves in molecular clouds. The importance of ambipolar diffusion on a length scale $\ell$ is governed by the ambipolar diffusion Reynolds number,
$R_{\rm AD}=\ell/\ell_{\rm AD}$, where $\ell_{\rm AD}$ is the characteristic length scale for ambipolar diffusion. The logarithmic mean of the AD Reynolds number in a sample of 15 molecular clumps with measured magnetic fields (Crutcher 1999) is 17, comparable to the theoretically expected value. We identify several regimes of ambipolar diffusion in a turbulent medium, depending on the ratio of the flow time to collision times between ions and neutrals; the clumps observed by Crutcher (1999) are all in the standard regime of ambipolar diffusion, in which the neutrals and ions are coupled over a flow time. We have carried out two-fluid simulations of ambipolar diffusion in isothermal, turbulent boxes for a range of values of $R_{\rm AD}$. The mean Mach numbers were fixed at ${\cal M}=3$ and ${\cal M}_A=0.67$; self-gravity was not included. We study the properties of overdensities--i.e., clumps--in the simulation and show that the slope of the higher-mass portion of the clump mass spectrum increases as $R_{\rm AD}$ decreases, which is qualitatively consistent with Padoan et al. (2007)'s finding that the mass spectrum in hydrodynamic turbulence is significantly steeper than in ideal MHD turbulence. For a value of $R_{\rm AD}$ similar to the observed value, we find a slope that is consistent with that of the high-mass end of the Initial Mass Function for stars. However, the value we find for the spectral index in our ideal MHD simulation differs from theirs, presumably because our simulations have different initial conditions. This suggests that the mass spectrum of the clumps in the Padoan et al. (2007) turbulent fragmentation model for the IMF depends on the environment, which would conflict with evidence for a universal IMF. In addition, we give a general discussion of how the results of simulations of magnetized, turbulent, isothermal boxes can be scaled to physical systems. Each physical process that is introduced into the simulation, such as ambipolar diffusion, introduces a dimensionless parameter, such as $R_{\rm AD}$, which must be fixed for the simulation, thereby reducing the number of scaling parameters by one. We show that the importance of self-gravity is fixed in any simulation of ambipolar diffusion; it is not possible to carry out a simulation in which self-gravity and ambipolar diffusion are varied independently unless the ionization is a free parameter. We show that our simulations apply to small regions in molecular clouds, generally with $\ell_0\le 0.4$~pc and $M\le 25\;M_\odot$. A general discussion of the scaling relations for magnetized, isothermal, turbulent boxes, including self-gravitating systems, is given in the Appendix.}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJ }
%% If preprints are available on the WWW you can give the web %% direction here.
http://arxiv.org/abs/1007.2032
\v5
{\large\bf{Wall emission in circumbinary disks:
the case of CoKu Tau/4}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Erick Nagel$^1$, Paola D'Alessio$^2$, Nuria Calvet$^3$,
Catherine Espaillat$^4$, Ben Sargent$^5$, Jes\'us Hern\'andez$^6$, and
William J. Forrest$^7$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Departamento de Astronom\'\i a, Universidad de Guanajuato,
Guanajuato,cGto, M\'exico 36240} \\
$^2$ {Centro de Radioastronom\'\i a y Astrof\'\i sica, UNAM, Morelia,
Michoac\'an, M\'exico 58089} \\
$^3$ {Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA} \\
$^4$ {Harvard-Smithsonian Center for Astrophysics, 60 Garden Street,
MS-78, Cambridge, MA, 02138, USA} \\
$^5$ {Space Telescope Science Institute, Baltimore, MD 21218, USA} \\
$^6$ {Centro de Investigaciones de Astronom\'\i a, M\'erida 5101-A,
Venezuela} \\
$^7$ {Department of Physics and Astronomy, University of Rochester,
Rochester, NY 14627, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: erick {\em at} astro.ugto.mx}
%% Within the following brackets you place your text:
{A few years ago, the mid-IR spectrum of a Weak Line T Tauri Star, CoKu
Tau/4, was explained as emission
from the inner wall of a {\it circumstellar} disk, with the inner disk
truncated at
$\sim$ 10 AU. Based on the SED shape and the assumption that it was
produced
by a single star and its disk, CoKu Tau/4 was classified as a prototypical
transitional disk, with a clean inner hole possibly carved out by a
planet, some other orbiting body, or by photodissociation.
However, recently it has been discovered that CoKu Tau/4 is a close
binary
system. This implies that the observed mid-IR SED is probably produced by
the {\it circumbinary} disk.
The aim of the present paper is to model the SED
of CoKu Tau/4 as arising from the inner wall of a circumbinary disk, with
parameters constrained
by what is known about the central stars and by a dynamical model for the
interaction between these stars and their surrounding disk.
We lack a physical prescription for the shape of the wall, thus, here we
use a
simplified and unrealistic assumption: the wall is vertical.
In order to fit the Spitzer IRS SED,
the binary orbit should be almost circular, implying a small mid-IR
variability (10 \%) related to the variable distances
of the stars to the inner wall of the circumbinary disk.
In the context of the present model, higher eccentricities would imply
that the stars are farther from the wall,
the latter being too cold to explain the observed SED.
Our models suggest that the inner wall of CoKu Tau/4 is located at $1.7
a$, where
$a$ is the semi-major axis of the binary system ($a\sim 8AU$).
A small amount of optically thin dust in the hole ($\lesssim 0.01$ lunar
masses) helps to improve the fit to the 10 $\mu$m silicate band.
The dust properties are not well constrained, since depend on the
extinction law, but standard abundances of silicates (olivine or pyroxene)
and graphite explains the observed SED.
Also, we find that water ice should be absent or have a
very small abundance (a dust to gas mass ratio $\lesssim 5.6 \times
10^{-5}$).
In general, for a binary system with eccentricity $e > 0$, the model predicts
mid-IR variability with periods similar to orbital timescales, assuming
that thermal equilibrium is reached instantaneously. }
% Here you write which journal accepted your paper, for example:
{ Accepted by Astrophysical Journal }
%% If preprints are available on the WWW you can give the web
%% direction here.
\clearpage
%%--------SubmissionID=2386----------------
%% Title
{\large\bf{Disk Imaging Survey of Chemistry with SMA (DISCS): \\I.
Taurus Protoplanetary Disk Data}}
%% Authors
{\bf{ Karin I. \"Oberg$^{1}$, Chunhua Qi$^{1}$, Jeffrey K.J. Fogel$^{2}$, Edwin A. Bergin$^{2}$, Sean M. Andrews$^{1}$, Catherine Espaillat$^{1}$, Tim A. van Kempen$^{1}$, David J. Wilner$^{1}$ and Ilaria Pascucci$^{3}$}}
%% Institutions
$^1$ {Harvard-Smithsonian Center for Astrophysics, Cambridge, USA} \\
$^2$ {University of Michigan, Ann Arbor, USA} \\
$^3$ {Johns Hopkins University, Baltimore, USA}
%% Email
{E-mail contact: koberg {\em at} cfa.harvard.edu}
%% LATEX COMMANDS
%% Abstract body
{Chemistry plays an important role in the structure and evolution of
protoplanetary disks, with implications for the composition of
comets and planets. This is the first of a series of papers based on
data from DISCS, a Submillimeter Array survey of the chemical
composition of protoplanetary disks. The six Taurus sources in the
program (DM Tau, AA Tau, LkCa 15, GM Aur, CQ Tau and MWC 480) range
in stellar spectral type from M1 to A4 and offer an opportunity to
test the effects of stellar luminosity on the disk chemistry. The
disks were observed in 10 different lines at $\sim$3~arcsec
resolution and an rms of $\sim100$ mJy~beam$^{-1}$ at $\sim0.5$
km~s$^{-1}$. The four brightest lines are CO 2--1, HCO$^+$ 3--2, CN
2$_{3 \: 3/4/2}-1_{2 \: 2/3/1}$ and HCN 3--2 and these are detected
toward all sources (except for HCN toward CQ Tau). The weaker lines
of CN 2$_{2 \: 2}-1_{1 \: 1}$, DCO$^+$ 3--2, N$_2$H$^+$ 3--2,
H$_2$CO 3$_{0 \: 3}-2_{0 \: 2}$ and 4$_{1 \: 4}-3_{1 \: 3}$ are
detected toward two to three disks each, and DCN 3--2 only toward
LkCa 15. CH$_3$OH $4_{2\: 1}-3_{1\: 2}$ and $c$-C$_3$H$_2$ are not
detected. There is no obvious difference between the T Tauri and
Herbig Ae sources with regard to CN and HCN intensities. In
contrast, DCO$^+$, DCN, N$_2$H$^+$ and H$_2$CO are detected only
toward the T Tauri stars, suggesting that the disks around Herbig Ae
stars lack cold regions for long enough timescales to allow for
efficient deuterium chemistry, CO freeze-out, and grain chemistry.}
% Journal
{ Accepted by Astrophysical Journal}
%% Preprints URL
http://arxiv.org/abs/1007.1476
\v5
%%--------SubmissionID=2387----------------
%% Title
{\large\bf{The effect of H$_2$O on ice photochemistry}}
%% Authors
{\bf{ Karin I. \"Oberg$^{1,2}$, Ewine F. van Dishoeck$^{3,4}$, Harold Linnartz$^{2}$ and Stefan Andersson$^{5}$}}
%% Institutions
$^1$ {Harvard-Smithsonian Center for Astrophysics, Cambridge, USA} \\
$^2$ {Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, Netherlands} \\
$^3$ {Leiden Observatory, Leiden University, Netherlands} \\
$^4$ {Max-Planck Institute f\"ur Extraterrestrische Physik, Garching, Germany} \\
$^5$ {INTEF Materials and Chemistry, Trondheim, Norway}
%% Email
{E-mail contact: koberg {\em at} cfa.harvard.edu}
%% LATEX COMMANDS
%% Abstract body
{UV irradiation of simple ices is proposed to efficiently produce
complex organic species during star- and planet-formation. Through a
series of laboratory experiments, we investigate the effects of the
H$_2$O concentration, the dominant ice constituent in space, on the
photochemistry of more volatile species, especially CH$_4$, in ice
mixtures. In the experiments, thin ($\sim$40~ML) ice mixtures, kept
at 20--60~K, are irradiated under ultra-high vacuum conditions with
a broad-band UV hydrogen discharge lamp. Photodestruction cross
sections of volatile species (CH$_4$ and NH$_3$) and production
efficiencies of new species (C$_2$H$_6$, C$_2$H$_4$, CO, H$_2$CO,
CH$_3$OH, CH$_3$CHO and CH$_3$CH$_2$OH) in water-containing ice
mixtures are determined using reflection-absorption infrared
spectroscopy during irradiation and during a subsequent slow
warm-up. The four major effects of increasing the H$_2$O
concentration are 1) an increase of the destruction efficiency of
the volatile mixture constituent by up to an order of magnitude due
to a reduction of back reactions following photodissociation, 2) a
shift to products rich in oxygen e.g. CH$_3$OH and H$_2$CO, 3)
trapping of up to a factor of five more of the formed radicals in
the ice and 4) a disproportional increase in the diffusion barrier
for the OH radical compared to the CH$_3$ and HCO radicals. The
radical diffusion temperature dependencies are consistent with
calculated H$_2$O-radical bond strengths. All the listed effects are
potentially important for the production of complex organics in
H$_2$O-rich icy grain mantles around protostars and should thus be
taken into account when modeling ice chemistry.}
% Journal
{ Accepted by Astrophysical Journal}
%% Preprints URL
http://arxiv.org/abs/1006.2190
\v5
%%--------SubmissionID=2388----------------
%% Title
{\large\bf{Mapping the column density and dust temperature structure of IRDCs with Herschel}}
%% Authors
{\bf{ N. Peretto$^{1,2}$, G.A. Fuller$^{1}$, R. Plume$^{3}$ and the Hi-GAL consortium$^{4}$}}
%% Institutions
$^1$ {Jodrell Bank Centre for Astrophysics, University of Manchester, UK} \\
$^2$ {Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d'Astrophysique, C.E. Saclay, France} \\
$^3$ {Department of Physics and Astronomy, University of Calgary, Canada} \\
$^4$ {INAF-IFSI, Roma, Italy}
%% Email
{E-mail contact: nicolas.peretto {\em at} cea.fr}
%% LATEX COMMANDS
%% Abstract body
{Infrared dark clouds (IRDCs) are cold and dense reservoirs of gas
potentially available to form stars. Many of these clouds are likely
to be pristine structures representing the initial conditions for
star formation. The study presented here aims to construct and
analyze accurate column density and dust temperature maps of IRDCs
by using the first Herschel data from the Hi-GAL galactic plane
survey. These fundamental quantities, are essential for
understanding processes such as fragmentation in the early stages of
the formation of stars in molecular clouds. We have developed a
simple pixel-by-pixel SED fitting method, which accounts for the
background emission. By fitting a grey-body function at each
position, we recover the spatial variations in both the dust column
density and temperature within the IRDCs. This method is applied to
a sample of 22 IRDCs exhibiting a range of angular sizes and peak
column densities. Our analysis shows that the dust temperature
decreases significantly within IRDCs, from background temperatures of
20-30 K to minimum temperatures of 8-15 K within the clouds, showing
that dense molecular clouds are not isothermal. Temperature
gradients have most likely an important impact on the fragmentation
of IRDCs. Local temperature minima are strongly correlated with
column density peaks, which in a few cases reach N$_{H_2} = 1\times
10^{23}$~cm$^{-2}$ , identifying these clouds as candidate massive
prestellar cores. Applying this technique to the full Hi-GAL data
set will provide important constraints on the fragmentation and
thermal properties of IRDCs, and help identify hundreds of massive
prestellar core candidates.}
% Journal
{ Accepted by A\&A}
%% Preprints URL
http://arxiv.org/pdf/1005.1506v1
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Faint Collimated Herbig-Haro Jets from Visible Stars in L1641
}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{Bo Reipurth$^1$, Colin Aspin$^1$, John Bally$^2$, John J. Tobin$^3$, and Josh Walawender$^1$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Institute for Astronomy, University of Hawaii at Manoa, 640 N. Aohoku Place, HI 96720, USA} \\
$^2$ {Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309, USA} \\
$^3$ {Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: reipurth {\em at} ifa.hawaii.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your tex:
{ A population of 11 faint, collimated jets has been discovered in the
northern part of the L1641 cloud in the region of HH 1/2, HH 34, and
the L1641-N cluster. These jets were missed in previous imaging
surveys on account of their weak emission, and they were discovered
only on deep exposures with the Subaru 8m telescope. With these new
faint jets, the number of HH flows within the area surveyed has
doubled. This suggests that collimated jets from young stars may be
more common than assumed so far. It is noteworthy that all of the
jets are associated with optically visible stars with r-magnitudes
ranging from 13.8 to 22.0. The driving sources of jets in regions
flooded by ultraviolet radiation from nearby OB stars are known to
be excavated by photo-ionization, and in three cases remnant H$\alpha$
emission envelopes are found associated with the sources, although
the more benign environment in the region observed here, about 10 pc
distant from the Orion Nebula Cluster, makes the optical visibility
of all these sources rather surprising. Such faint jets from visible
stars represent either the final vestiges of the outflow phenomenon,
or they are triggered by disturbances of the remnant disks, possibly
initiated by the orbital evolution of binaries that spiral in to
form close binaries. Among the known H~ emission stars within the
region surveyed, 8\% are found to be associated with jets. }
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J. }
%% If preprints are available on the WWW you can give the web
%% direction here:
Http://www.ifa.hawaii.edu/publications/preprints/10preprints/Reipurth\_10-104.pdf
\clearpage
%%--------SubmissionID=2401----------------
%% Title
{\large\bf{On the observability of T Tauri accretion shocks in the X-ray band}}
%% Authors
{\bf{ G. G. Sacco$^{1, 2}$, S. Orlando$^{2}$, C. Argiroffi$^{3, 2}$, A. Maggio$^{2}$, G. Peres$^{3,2}$, F. Reale$^{3,2}$ and R. L. Curran$^{2,4}$}}
%% Institutions
$^1$ {Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, 14623 NY, USA} \\
$^2$ {INAF-Osservatorio Astronomico di Palermo, Piazza del Parlamento, 1, 90134, Palermo, Italy} \\
$^3$ {DSFA-Universita' degli Studi di Palermo, Piazza del Parlamento, 1, 90134, Palermo, Italy} \\
$^4$ {Department of Physics, Rochester Institute of Technology, 54 Lomb Memorial Dr., Rochester, NY 14623, USA}
%% Email
{E-mail contact: sacco {\em at} cis.rit.edu}
%% LATEX COMMANDS
%% Abstract body
{\em Context}. High resolution X-ray observations of classical T Tauri stars
(CTTSs) show a soft X-ray excess due to high density plasma ($n_{\rm
e}=10^{11}-10^{13}$ cm$^{-3}$). This emission has been attributed to
shock-heated accreting material impacting onto the stellar surface.\\
% aims heading (mandatory)
{\em Aims}. We investigate the observability of the shock-heated accreting material
in the X-ray band as a function of the accretion stream properties
(velocity, density, and metal abundance) in the case of plasma-$\beta
\ll 1$ (thermal pressure $\ll$ magnetic pressure) in the post-shock
zone.\\
% methods heading (mandatory)
{\em Methods}. We use a 1-D hydrodynamic model describing the impact of an accretion
stream onto the chromosphere of a CTTS, including the effects of radiative
cooling, gravity stratification and thermal conduction. We explore the
space of relevant parameters and synthesize from the model results the
X-ray emission in the $[0.5-8.0]$ keV band and in the resonance lines
of O~VII (21.60 {\AA}) and Ne~IX (13.45 {\AA}), taking
into account the absorption from the chromosphere.\\
% results heading (mandatory)
{\em Results}. The accretion stream properties largely influence the temperature
and the stand-off height of the shocked slab and its sinking in the
chromosphere, determining the observability of the shocked plasma
affected by chromospheric absorption. Our model predicts that X-ray
observations preferentially detect emission from low density and high
velocity shocked accretion streams due to the large absorption of
dense post-shock plasma. In all the cases examined, the post-shock zone
exhibits quasi-periodic oscillations due to thermal instabilities with
periods ranging from $3\times 10^{-2}$ to $4\times 10^3$ s. In the case
of inhomogeneous streams and $\beta \ll 1$, the shock oscillations are
hardly detectable.\\
% conclusions heading (optional), leave it empty if necessary
{\em Conclusions}. We suggest that, if accretion streams are inhomogeneous, the selection effect introduced by the absorption on observable plasma components
may easily explain the discrepancy between the accretion rate measured
by optical and X-ray data as well as the different densities measured
using different He-like triplets in the X-ray band.
% Journal
{ Accepted by Astronomy \& Astrophysics}
%% Preprints URL
http://arxiv.org/abs/1007.2423
\v5
%%--------SubmissionID=2385----------------
%% Title
{\large\bf{Dynamic star formation in the massive DR21 filament}}
%% Authors
{\bf{ N. Schneider$^{1}$, T. Csengeri$^{1}$, S. Bontemps$^{2}$, F. Motte$^{1}$, R. Simon$^{3}$, P. Hennebelle$^{4}$, C. Federrath$^{5}$ and R. Klessen$^{5,6}$}}
%% Institutions
$^1$ {IRFU/SAp CEA-Saclay, Laboratoire AIM, CEA/DSM - INSU/CNRS, France} \\
$^2$ {OASU/LAB-UMR5804 Bordeaux, France} \\
$^3$ {I. Physikalisches Institut Koeln, Univ. Koeln, Germany} \\
$^4$ {Laboratoire de radioastronomie, UMR CNRS 8112, Observatoire de Paris, France} \\
$^5$ {Zentrum fuer Astronomie Univ. Heidelberg, Inst. fuer Theor. Astrophysik, Heidelberg, Germany} \\
$^6$ {Kavli Institute for Particle Astrophysics and Cosmology, Stanford, USA}
%% Email
{E-mail contact: nschneid {\em at} cea.fr}
%% LATEX COMMANDS
%% Abstract body
{The formation of massive stars is a highly complex process in which
it is unclear whether the star-forming gas is in global
gravitational collapse or an equilibrium state supported by
turbulence and/or magnetic fields. In addition, magnetic fields may
play a decisive role in the star-formation process since they
influence the efficiency of gas infall onto the protostar.
By studying one of the most massive and dense star-forming regions in
the Galaxy at a distance of less than 3 kpc, i.e. the filament
containing the well-known sources DR21 and DR21(OH), we attempt
to obtain observational evidence to help us to discriminate between
these two views.
We use molecular line data from our $^{13}$CO 1$\to$0, CS 2$\to$1,
and N$_2$H$^+$ 1$\to$0 survey of the Cygnus X region obtained with the
FCRAO and high-angular resolution observations in isotopomeric lines
of CO, CS, HCO$^+$, N$_2$H$^+$, and H$_2$CO, obtained with the IRAM
30m telescope, to investigate the distribution of the different phases
of molecular gas. Gravitational infall is identified by the presence
of inverse P Cygni profiles that are detected in optically thick lines,
while the optically thinner isotopomers are found to reach a peak
in the self-absorption gap.
We observe a complex velocity field and velocity dispersion in the
DR21 filament in which regions of the highest column-density, i.e., dense
cores, have a lower velocity dispersion than the surrounding gas and
velocity gradients that are not (only) due to rotation. Infall
signatures in optically thick line profiles of HCO$^+$ and $^{12}$CO
are observed along and across the whole DR21 filament. By modelling the
observed spectra, we obtain a typical infall speed of $\sim$0.6 km
s$^{-1}$ and mass accretion rates of the order of a few 10$^{-3}$
M$_\odot$ yr$^{-1}$ for the two main clumps constituting the filament.
These massive clumps (4900 and 3300 M$_\odot$ at densities of around
10$^5$ cm$^{-3}$ within 1 pc diameter) are both gravitationally
contracting (with free-fall times much shorter than sound crossing times
and low virial parameter $\alpha$). The more massive of the clumps,
DR21(OH), is connected to a sub-filament, apparently 'falling' onto
the clump. This filament runs parallel to the magnetic field.
All observed kinematic features in the DR21 filament (velocity field,
velocity dispersion, and infall), its filamentary morphology, and the
existence of (a) sub-filament(s) can be explained if the DR21
filament was formed by the convergence of flows on large scales and is
now in a state of global gravitational collapse. Whether this
convergence of flows originated from self-gravity on larger scales or
from other processes cannot be determined by the present study. The
observed velocity field and velocity dispersion are consistent with
results from (magneto)-hydrodynamic simulations where the cores lie
at the stagnation points of convergent turbulent flows.}
% Journal
{ Accepted by Astronomy and Astrophysics}
%% Preprints URL
http://lanl.arxiv.org/abs/1003.4198
\v5
%%--------SubmissionID=2369----------------
%% Title
{\large\bf{A bipolar outflow from the massive protostellar core W51e2-E}}
%% Authors
{\bf{ Hui Shi$^{1}$, Jun-Hui Zhao$^{2}$ and Jinlin Han$^{1}$}}
%% Institutions
$^1$ {Nat. Astron. Obs., Chinese Academy
of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China} \\
$^2$ {Harvard-Smithsonian Center for Astrophysics, 60
Garden Street, Cambridge, MA 02138, USA}
%% Email
{E-mail contact: shihui {\em at} nao.cas.cn}
%% LATEX COMMANDS
%% Abstract body
{We present high resolution images of the bipolar outflow in W51e2,
which are produced from the Submillimeter Array archival data observed
for CO(3-2) and HCN(4-3) lines with angular resolutions of
$0.8''\times0.6''$ and $0.3''\times0.2''$,
respectively. The images show that the powerful outflow originates
from the protostellar core W51e2-E rather than from the ultracompact
HII region W51e2-W. The kinematic timescale of the outflow from
W51e2-E is about 1000\,yr, younger than the age ($\sim$5000\,yr) of
the ultracompact HII region W51e2-W. A large mass loss rate of
$\sim1\times10^{-3}$M$_{\odot}$~yr$^{-1}$ and a high mechanical power
of 120\,L$_{\odot}$ are inferred, suggesting that an O star or a
cluster of B stars are forming in W51e2-E. The observed outflow
activity along with the inferred large accretion rate indicates that
at present W51e2-E is in a rapid phase of star formation.}
% Journal
{ Accepted by ApJL}
%% Preprints URL
http://arxiv.org/abs/1006.4058
\v5
%%--------SubmissionID=2381----------------
%% Title
{\large\bf{Debris Disks of Members of the Blanco 1 Open Cluster}}
%% Authors
{\bf{ J. R. Stauffer$^{1}$, L. M. Rebull$^{1}$, D. James$^{2}$, A. Noriega-Crespo$^{1}$, S. E. Strom$^{3}$, S. Wolk$^{4}$, M. Meyer$^{5}$, J. Carpenter$^{6}$, D. Barrado y Navascues$^{7}$, G. Micela$^{8}$, D. Backman$^{9}$ and P. Cargile$^{10}$}}
%% Institutions
$^1$ {SSC} \\
$^2$ {UH} \\
$^3$ {NOAO} \\
$^4$ {CXC} \\
$^5$ {UA/Zurich} \\
$^6$ {Caltech} \\
$^7$ {LAEFF} \\
$^8$ {INAF} \\
$^9$ {SETI} \\
$^{10}$ {Vanderbilt}
%% Email
{E-mail contact: stauffer {\em at} ipac.caltech.edu}
%% LATEX COMMANDS
%% Abstract body
{We have used the Spitzer Space Telescope to obtain Multiband Imaging
Photometer for Spitzer (MIPS) 24 um photometry for 37 members of the ~100 Myr
old open cluster Blanco 1. For the brightest 25 of these stars (where we have
3sigma uncertainties less than 15\%), we find significant mid-IR excesses for
eight stars, corresponding to a debris disk detection frequency of about 32\%.
The stars with excesses include two A stars, four F dwarfs and two G dwarfs.
The most significant linkage between 24 um excess and any other stellar
property for our Blanco 1 sample of stars is with binarity. Blanco 1 members
that are photometric binaries show few or no detected 24 um excesses whereas a
quarter of the apparently single Blanco 1 members do have excesses. We have
examined the MIPS data for two other clusters of similar age to Blanco 1 -- NGC
2547 and the Pleiades. The AFGK photometric binary star members of both of
these clusters also show a much lower frequency of 24 um excesses compared to
stars that lie near the single-star main sequence. We provide a new
determination of the relation between V-Ks color and Ks-[24] color for main
sequence photospheres based on Hyades members observed with MIPS. As a result
of our analysis of the Hyades data, we identify three low mass Hyades members
as candidates for having debris disks near the MIPS detection limit.}
% Journal
{ Accepted by ApJ}
%% Preprints URL
http://arxiv.org/abs/1007.0239
\v5
%%--------SubmissionID=2392----------------
%% Title
{\large\bf{Herschel/HIFI observations of spectrally resolved methylidyne signatures toward the high-mass star-forming core NGC\,6334I}}
%% Authors
{\bf{ M.H.D. van der Wiel$^{1,2}$, F.F.S. van der Tak$^{2,1}$, D.C. Lis$^{3}$ and the CHESS and HIFI teams$^{4}$}}
%% Institutions
$^1$ {Kapteyn Astronomical Institute, Groningen, NL} \\
$^2$ {SRON Netherlands Institute for Space Research, Groningen, NL} \\
$^3$ {California Institute of Technology, Pasadena, USA} \\
$^4$ {various}
%% Email
{E-mail contact: wiel {\em at} astro.rug.nl}
%% LATEX COMMANDS
\def\pow#1#2{#1$\times$10$^{#2}$}
\def\kms{$\mathrm{km}\,\mathrm{s}^{-1}$} % km/s
%% Abstract body
{\em Context.} In contrast to the more extensively studied dense star-forming cores, little is known about diffuse gas surrounding star-forming regions. \\
\emph{Aims.} We study the molecular gas in the Galactic high-mass star-forming region NGC\,6334I, which contains diffuse, quiescent components that are inconspicuous in widely used molecular tracers such as CO.\\
{\em Methods.} We present Herschel/HIFI observations of methylidyne
(CH) toward NGC\,6334I
observed as part of the 'Chemical Herschel Surveys of Star Forming Regions' (CHESS) key program. HIFI resolves each of the six hyperfine components of the lowest rotational transition ($J$=$\frac{3}{2}$--$\frac{1}{2}$) of CH, observed in both emission and absorption.\\
{\em Results.} The CH emission features appear close to the systemic velocity of NGC\,6334I, while its measured FWHM linewidth of 3\,\kms\ is smaller than previously observed in dense gas tracers such as NH$_3$ and SiO. The CH abundance in the hot core is $\sim$\pow{7}{-11}, two to three orders of magnitude lower than in diffuse clouds. While other studies find distinct outflows in, e.g., CO and H$_2$O toward NGC\,6334I, we do not detect any outflow signatures in CH. At least two redshifted components of cold absorbing material must be present at $-3.0$ and $+6.5$\,\kms\ to explain the absorption signatures. We derive a CH column density ($N_\mathrm{CH}$) of \pow{7}{13} and \pow{3}{13}\, cm$^{-2}$ for these two absorbing clouds. We find evidence of two additional absorbing clouds at $+8.0$ and $0.0$\,\kms, both with $N_\mathrm{CH}$ $\approx$\pow{2}{13}\, cm$^{-2}$. Turbulent linewidths for the four absorption components vary between 1.5 and 5.0\,\kms\ in FWHM. We constrain the physical properties and locations of the clouds by matching our CH absorbers with the absorption signatures seen in other molecular tracers.\\
{\em Conclusions.} In the hot core, molecules such as H$_2$O and CO
trace gas that is heated and dynamically influenced by outflow
activity, whereas the CH molecule traces more quiescent material. The
four CH absorbing clouds have column densities and turbulent
properties that are consistent with those of diffuse clouds: two are
located in the direct surroundings of NGC\,6334, and two are unrelated
foreground clouds. Local density and dynamical effects influence the
chemical composition of the physical components of NGC\,6334, which
causes some components to be seen in CH but not in other tracers, and
vice versa.
% Journal
{ Accepted by Astronomy \& Astrophysics Letters, HIFI special issue}
%% Preprints URL
http://arxiv.org/abs/1007.1539
\clearpage
%%--------SubmissionID=2390----------------
%% Title
{\large\bf{The burst mode of accretion and disk fragmentation in the early embedded stages of star formation}}
%% Authors
{\bf{ Eduard Vorobyov$^{1}$ and Shantanu Basu$^{2}$}}
%% Institutions
$^1$ {The Institute for Computational Astrophysics, Saint Mary's University, Halifax, Canada} \\
$^2$ {The University of Western Ontario, London, Canada}
%% Email
{E-mail contact: vorobyov {\em at} ap.smu.ca}
%% LATEX COMMANDS
%% Abstract body
{We revisit our original papers on the burst mode of accretion by
incorporating a detailed energy balance equation into a thin-disk
model for the formation and evolution of circumstellar disks around
low-mass protostars. Our model includes the effect of radiative
cooling, viscous and shock heating, and heating due to stellar and
background irradiation. Following the collapse from the prestellar
phase allows us to model the early embedded phase of disk formation
and evolution. During this time, the disk is susceptible to
fragmentation, depending upon the properties of the initial
prestellar core. Globally, we find that higher initial core angular
momentum and mass content favors more fragmentation, but higher
levels of background radiation can moderate the tendency to
fragment. A higher rate of mass infall onto the disk than that onto
the star is a necessary but not sufficient condition for disk
fragmentation. More locally, both the Toomre $Q$-parameter needs to
be below a critical value {\it and} the local cooling time needs to
be shorter than a few times the local dynamical time. Fragments that
form during the early embedded phase tend to be driven into the
inner disk regions, and likely trigger mass accretion and luminosity
bursts that are similar in magnitude to FU-Orionis-type or
EX-Lupi-like events. Disk accretion is shown to be an intrinsically
variable process, thanks to disk fragmentation, nonaxisymmetric
structure, and the effect of gravitational torques. The additional
effect of a generic $\alpha$-type viscosity acts to reduce burst
frequency and accretion variability, and is likely to not be viable
for values of $\alpha$ significantly greater than 0.01.}
% Journal
{ Accepted by The Astrophysical Journal}
%% Preprints URL
\vspace{0.3cm}
{\large\bf{Herschel observations of the hydroxyl radical (OH) in young stellar objects}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ S.F.~Wampfler$^1$, G.J.~Herczeg$^2$, S.~Bruderer$^1$, A.O.~Benz$^1$, E.F.~van~Dishoeck$^{2,3}$, L.E.~Kristensen$^3$, R.~Visser$^3$, S.D.~Doty$^4$, M. Melchior$^{1,5}$, T.A.~van~Kempen$^6$, U.A.~Y{\i}ld{\i}z$^3$, C.~Dedes$^1$, J.R.~Goicoechea$^7$, A.~Baudry$^8$, G.~Melnick$^6$, R.~Bachiller$^9$, M.~Benedettini$^{10}$, E.~Bergin$^{11}$, P.~Bjerkeli$^{12}$, G.A.~Blake$^{13}$, S.~Bontemps$^{8}$, J.~Braine$^{8}$, P.~Caselli$^{14,15}$, J.~Cernicharo$^{7}$, C.~Codella$^{15}$, F.~Daniel$^{7}$, A.M.~di~Giorgio$^{10}$, C.~Dominik$^{16,17}$, P.~Encrenaz$^{18}$, M.~Fich$^{19}$, A.~Fuente$^{20}$, T.~Giannini$^{21}$, Th.~de~Graauw$^{22}$, F.~Helmich$^{22}$, F.~Herpin$^8$, M.R.~Hogerheijde$^3$, T.~Jacq$^8$, D.~Johnstone$^{23,24}$, J.K.~J{\o}rgensen$^{25}$, B.~Larsson$^{26}$, D.~Lis$^{27}$, R.~Liseau$^{12}$, M.~Marseille$^{22}$, C.~M$^{\textrm c}$Coey$^{19,28}$, D.~Neufeld$^{29}$, B.~Nisini$^{21}$, M.~Olberg$^{9}$, B.~Parise$^{30}$, J.C.~Pearson$^{31}$, R.~Plume$^{32}$, C.~Risacher$^{22}$, J.~Santiago-Garc\'{i}a$^{33}$, P.~Saraceno$^{10}$, R.~Shipman$^{22}$, M.~Tafalla$^{9}$, F.F.S.~van der Tak$^{22,34}$, F.~Wyrowski$^{30}$, P.~Roelfsema$^{22}$, W.~Jellema$^{22}$, P.~Dieleman$^{22}$, E.~Caux$^{35,36}$, \ and J.~Stutzki$^{37}$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Institute for Astronomy, ETH Zurich, 8093 Zurich, Switzerland} \\
$^2$ {Max Planck Institut f\"{u}r Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany} \\
$^3$ {Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands} \\
$^4$ {Department of Physics and Astronomy, Denison University, Granville, OH, 43023, USA} \\
$^5$ {Institute of 4D Technologies, University of Applied Sciences NW, CH-5210 Windisch, Switzerland} \\
$^6$ {Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 42, Cambridge, MA 02138, USA} \\
$^7$ {Centro de Astrobiolog\'{\i}a. Departamento de Astrof\'{\i}sica. CSIC-INTA. Carretera de Ajalvir, Km 4, Torrej\'{o}n de Ardoz. 28850, Madrid, Spain.} \\
$^8$ {Universit\'{e} de Bordeaux, Laboratoire d'Astrophysique de Bordeaux, France; CNRS/INSU, UMR 5804, Floirac, France} \\
$^9$ {Observatorio Astron\'{o}mico Nacional (IGN), Calle Alfonso XII,3. 28014, Madrid, Spain} \\
$^{10}$ {INAF - Istituto di Fisica dello Spazio Interplanetario, Area di Ricerca di Tor Vergata, via Fosso del Cavaliere 100, 00133 Roma, Italy} \\
$^{11}$ {Department of Astronomy, The University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042, USA} \\
$^{12}$ {Department of Radio and Space Science, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden} \\
$^{13}$ {California Institute of Technology, Division of Geological and Planetary Sciences, MS 150-21, Pasadena, CA 91125, USA} \\
$^{14}$ {School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK} \\
$^{15}$ {INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy} \\
$^{16}$ {Astronomical Institute Anton Pannekoek, University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands} \\
$^{17}$ {Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands} \\
$^{18}$ {LERMA and UMR 8112 du CNRS, Observatoire de Paris, 61 Av. de l'Observatoire, 75014 Paris, France} \\
$^{19}$ {University of Waterloo, Department of Physics and Astronomy, Waterloo, Ontario, Canada} \\
$^{20}$ {Observatorio Astron\'{o}mico Nacional, Apartado 112, 28803 Alcal\'{a} de Henares, Spain} \\
$^{21}$ {INAF - Osservatorio Astronomico di Roma, 00040 Monte Porzio catone, Italy} \\
$^{22}$ {SRON Netherlands Institute for Space Research, PO Box 800, 9700 AV, Groningen, The Netherlands} \\
$^{23}$ {National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada} \\
$^{24}$ {Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 1A1, Canada} \\
$^{25}$ {Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, {\O}ster Voldgade 5-7, DK-1350 Copenhagen K., Denmark} \\
$^{26}$ {Department of Astronomy, Stockholm University, AlbaNova, 106 91 Stockholm, Sweden} \\
$^{27}$ {California Institute of Technology, Cahill Center for Astronomy and Astrophysics, MS 301-17, Pasadena, CA 91125, USA} \\
$^{28}$ {the University of Western Ontario, Department of Physics and Astronomy, London, Ontario, N6A 3K7, Canada} \\
$^{29}$ {Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA} \\
$^{30}$ {Max-Planck-Institut f\"{u}r Radioastronomie, Auf dem H\"{u}gel 69, 53121 Bonn, Germany} \\
$^{31}$ {Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA} \\
$^{32}$ {Department of Physics and Astronomy, University of Calgary, Calgary, T2N 1N4, AB, Canada} \\
$^{33}$ {Instituto de Radioastronom\'{i}a Milim\'{e}trica (IRAM), Avenida Divina Pastora 7, N\'{u}cleo Central, E-18012 Granada, Spain} \\
$^{34}$ {Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV, Groningen, The Netherlands} \\
$^{35}$ {Centre d'Etude Spatiale des Rayonnements, Universit\'e de Toulouse [UPS], 31062 Toulouse Cedex 9, France} \\
$^{36}$ {CNRS/INSU, UMR 5187, 9 avenue du Colonel Roche, 31028 Toulouse Cedex 4, France} \\
$^{37}$ {KOSMA, I. Physik. Institut, Universit\"{a}t zu K\"{o}ln, Z\"{u}lpicher Str. 77, D 50937 K\"{o}ln, Germany}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: wampfler{\em at} astro.phys.ethz.ch}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{`Water in Star-forming regions with Herschel' (WISH) is a Herschel Key Program investigating the water chemistry in young stellar objects (YSOs) during protostellar evolution. Hydroxyl (OH) is one of the reactants in the chemical network most closely linked to the formation and destruction of H$_2$O.
High-temperature ($T > 250~\mathrm{K}$) chemistry connects OH and H$_2$O through the OH + H$_2$ $\Leftrightarrow$ H$_2$O + H reactions. Formation of H$_2$O from OH is efficient in the high temperature regime found in shocks and the innermost part of protostellar envelopes. Moreover, in the presence of UV photons, OH can be produced from the photo-dissociation of H$_2$O through H$_2$O + $\gamma_{\mathrm{UV}}$ $\Rightarrow$ OH + H.\\
High-resolution spectroscopy of the 163.12$~\mu$m triplet of OH towards HH~46 and NGC~1333~IRAS~2A was carried out with the Heterodyne Instrument for the Far Infrared (HIFI) on board the Herschel Space Observatory. The low- and intermediate-mass protostars HH~46, TMR~1, IRAS~15398-3359, DK~Cha, NGC~7129~FIRS~2 and NGC~1333~IRAS~2A were observed with the Photodetector Array Camera and Spectrometer (PACS) on Herschel in four transitions of OH and two [OI] lines.\\
The OH transitions at 79, 84, 119, and 163$~\mu$m and [OI] emission at 63 and 145$~\mu$m were detected with PACS towards the class I low-mass YSOs as well as the intermediate-mass and class I Herbig Ae sources. No OH emission was detected from the class 0 YSO NGC~1333~IRAS~2A, though the $119~\mu$m was detected in absorption. With HIFI, the 163.12$~\mu$m was not detected from HH~46 and only tentatively detected from NGC~1333~IRAS~2A.
The combination of the PACS and HIFI results for HH~46 constrains the line width (FWHM $>$ 11$~$km~s$^{-1}$) and indicates that the OH emission likely originates from shocked gas. This scenario is supported by trends of the OH flux increasing with the [OI] flux and the bolometric luminosity, as found in our sample. \\
Similar OH line ratios for most sources suggest that OH has comparable excitation temperatures despite the different physical properties of the sources.
}
% Here you write which journal accepted your paper, for example:
{Accepted by Astronomy \& Astrophysics (Herschel HIFI special issue) }
%% If preprints are available on the WWW you can give the web
%% direction here.
{http://arxiv.org/abs/1007.2198}
\v5
%%--------SubmissionID=2379----------------
%% Title
{\large\bf{Dependence of the Turbulent Velocity Field on Gas Density in L1551}}
%% Authors
{\bf{ Atsushi Yoshida$^{1}$, Yoshimi Kitamura$^{2}$, Yoshito Shimajiri$^{3, 4}$ and Ryohei Kawabe$^{4, 5}$}}
%% Institutions
$^1$ {Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8551, Japan} \\
$^2$ {Institute of Space and Astronautical Science/Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan} \\
$^3$ {Department of Astronomy, School of Science, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan} \\
$^4$ {Nobeyama Radio Observatory, Minamimaki, Minamisaku, Nagano 384-1805, Japan} \\
$^5$ {National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588, Japan}
%% Email
{E-mail contact: ayoshida {\em at} geo.titech.ac.jp}
%% LATEX COMMANDS
%% Abstract body
q{We have carried out mapping observations of the entire L1551
molecular cloud with about 2 pc $\times$ 2 pc size in the
$^{12}$CO(1-0) line with the Nobeyama 45 m radio telescope at the
high effective resolution of 22$''$ (corresponding to 0.017 pc at
the distance of 160 pc), and analyzed the $^{12}$CO data together
with the $^{13}$CO(1-0) and C$^{18}$O(1-0) data from the Nobeyama
Radio Observatory database. We derived the new non-thermal line
width$-$size relations, $\sigma_{\rm NT} ¥propto L^{\gamma}$, for
the three molecular lines, corrected for the effect of optical depth
and the line-of-sight integration. To investigate the
characteristic of the intrinsic turbulence, the effects of the
outflows were removed. The derived relations are ($\sigma_{\rm
NT}$/km s$^{-1}$) = (0.18 $\pm$ 0.010)($L$/pc)$^{0.45 \pm 0.095}$,
(0.20 $\pm$ 0.020)($L$/pc)$^{0.48 \pm 0.091}$, and (0.22 $\pm$
0.050)($L$/pc)$^{0.54 \pm 0.21}$ for the $^{12}$CO, $^{13}$CO, and
C$^{18}$O lines, respectively, suggesting that the line width$-$size
relation of the turbulence very weakly depends on our observed
molecular lines, i.e., the relation does not change between the
density ranges of 10$^{2}$ $-$ 10$^{3}$ and 10$^{3}$ $-$ 10$^{4}$
cm$^{-3}$. In addition, the relations indicate that incompressible
turbulence is dominant at the scales smaller than 0.6 pc in L1551.
The power spectrum indices converted from the relations, however,
seem to be larger than that of the Kolmogorov spectrum for
incompressible flow. The disagreement could be explained by the
anisotropy in the turbulent velocity field in L1551, as expected in
MHD turbulence. Actually, the autocorrelation functions of the
centroid velocity fluctuations show larger correlation along the
direction of the magnetic field measured for the whole Taurus cloud,
which is consistent with the results of numerical simulations for
incompressible MHD flow.}
% Journal
{ Accepted by ApJ}
%% Preprints URL
\vspace{3cm}
\fboxrule0.02cm
\fboxsep0.4cm
\fbox{\rule[-0.9cm]{0.0cm}{1.8cm}{\parbox{16cm}
{The Star Formation Newsletter is a vehicle for fast distribution of
information of interest for astronomers working on star formation
and molecular clouds. You can submit material for the following
sections: {\em Abstracts of recently accepted papers} (only for
papers sent to refereed journals), {\em Abstracts of recently
accepted major reviews} (not standard conference contributions),
{\em Dissertation Abstracts} (presenting abstracts of new Ph.D
dissertations), {\em Meetings} (announcing meetings broadly of
interest to the star and planet formation and early solar system
community), {\em New Jobs} (advertising jobs specifically
aimed towards persons within the areas of the Newsletter), and {\em Short
Announcements} (where you can inform or request information from
the community). \\
{\bf Latex macros for submitting abstracts and dissertation abstracts
(by e-mail to reipurth@ifa.hawaii.edu) are appended to each issue of
the newsletter. You can also submit via the Newsletter web interface
at http://www2.ifa.hawaii.edu/star-formation/index.cfm }. \\
The Star Formation Newsletter is available on the World Wide Web at
http://www.ifa.hawaii.edu/users/reipurth/newsletter.htm.
}}}
\clearpage
\begin{center}
{\Large\em Dissertation Abstracts}
\end{center}
\vspace{2cm}
%%--------SubmissionID=2393----------------
\begin{center}
%% Title
{\Large\bf{Circumstellar Disk Structure and Evolution through Resolved Submillimeter Observations}}
\vspace*{0.5cm}
%% Author
{\bf{ A. Meredith Hughes }}
%% Institution
{Harvard University}
%% Current Address
{60 Garden St. MS-10, Cambridge, MA 02138}
%% New Address
{Address as of 30 Aug 2010: UC Berkeley Dept. of Astronomy, 601 Campbell Hall, Berkeley, CA 94720}
%% Email
{Electronic mail: mhughes {\em at} cfa.harvard.edu}
%% Adviser
{Ph.D dissertation directed by: David J. Wilner}
%% Month/Year
{Ph.D degree awarded: May 2010}
\vspace*{0.8cm}
\end{center}
%% LATEX COMMANDS
%% Body
{Circumstellar disks provide the reservoirs of raw material and
determine conditions for the formation of nascent planetary systems.
This thesis presents observations from millimeter-wavelength
interferometers, particularly the Submillimeter Array, that address
the following outstanding problems in the study of protoplanetary
disks: (1) constraining the physical mechanisms driving the viscous
transport of material through the disk, and (2) carrying out
detailed studies of 'transitional' objects between the gas-rich
protoplanetary and tenuous, dusty debris disk phases to better
understand how gas and dust are cleared from the system. We study
accretion processes in three complementary ways: using spatially
resolved observations of molecular gas lines at high spectral
resolution to determine the magnitude and spatial distribution of
turbulence in the disk; using polarimetry to constrain the magnetic
properties of the outer disk in order to evaluate whether the MRI is
a plausible origin for this turbulence; and investigating the gas
and dust distribution at the outer disk edge in the context of
self-similar models of accretion disk structure and evolution. The
studies of transition disks use spatially resolved observations to
study the detailed structure of the gas and dust in systems that are
currently in the process of clearing material. We obtain snapshots
of the inside-out clearing of gas and dust in several systems, and
compare our observations with the theoretical predictions generated
for different disk clearing mechanisms. Our observations are
generally consistent with the characteristics predicted for viscous
transport driven by the magnetorotational instability and disk
clearing accomplished through the dual action of giant planet
formation and photoevaporation by energetic radiation from the
star.}
%% URL
https://www.cfa.harvard.edu/$\sim$mhughes/download/amh\_thesis.pdf
\clearpage
\begin{center}
{\Large\em Meetings}
%\end{center}
\vspace*{1cm}
{\bf First Announcement}
%% Title
{\Large\bf{CPS 7th International School of Planetary Sciences}}
\vspace*{0.5cm}
%\end{center}
%% Body
{\bf https://www.cps-jp.org/\~{}pschool/pub/2011-01-10/index.html}
{\bf Date: 10 -- 15 January 2011}\\
{\bf Venue: Seapal Suma, a casual seaside resort located in the west part of Kobe, Japan}\\
\end{center}
Address: 1-1-1 Sumaura-dori, Suma, Kobe 654-0055 Japan\\
Phone: +81 78 731 6815 / Fax: +81 78 734 1896\\
Japanese site:
http://www.seapalsuma.com/?\\
English site: http://web.travel.rakuten.co.jp/portal/my/info\_page\_e.Eng?f\_no=13907\&f\_ptn1=\&f\_teikei= \\
Objective and Scope:\\
The objective of CPS International School of Planetary Sciences is to promote education and research in planetary sciences for highly motivated graduate students and young researchers worldwide. It will offer them an opportunity to interact with leading scientists in a specific field of the year. Note that 'Planetary Sciences' includes astronomy (astrophysics, astrochemistry, astrobiology, etc.), geosciences, space science, and other related fields.
Topic of the coming school:\\
Theory of Stellar Evolution and Its Applications -- from the First Stars to Planet-Hosting Stars and Gas Giant Planets
The main part of the school will be a series of lectures on the
structure and evolution of stars with various masses including gas
giant planets and on the effects of mass loss and stellar rotation
upon them. Then a series of lectures follow on their contributions to
the nucleosynthesis and chemical evolution of the Milky Way and dwarf
galaxies in the local group and to the evolutionary characteristics of
planet-hosting stars from theoretical and observational viewpoints.
The development of our understandings in these fields has been
achieved by recent observations with large ground-based telescopes and
space telescopes and owing to large-scaled surveys of metal-poor
stars, supernova searches and searches for exo-planetary systems.
CPS 7th International School has a special session dedicated to the
memory of Prof. Chushiro Hayashi who was one of the founders of the
theory of stellar evolution and passed away in 2010.
Internationally well-established experts in various fields will review
recent progress in our understandings of those fields. The lecturers
and their topics are listed below:
Daiichiro Sugimoto (The University of Tokyo, Japan)\\
---Why the Stars and the Universe evolve? --- Fundamentals of Stellar Structure and Evolution and Their Gravothermal Natures
Peter R. Wood (Australian National University, Australia)\\
---Evolution and Mass Loss of Low- and Intermediate-Mass Stars
Georges Meynet (University of Geneva, Switzerland)\\
---Evolution of Massive Stars and the Effects of Rotation
Stanley P. Owocki (University of Delaware, USA)\\
---Mass Loss from Massive Stars
Alexander Heger (University of Minnesota, USA)\\
---Explosive Nucleosynthesis
Martin Asplund (Max-Planck-Institut f\"{u}r Astrophysik, Germany)\\
---Solar Abundances, Solar Twins, and Planet Harboring Stars
Arlette Noels (Universit\'{e} de Li\`{e}ge, Belgium)\\
---Seismology and Oscillations of Stars
Jonathan J. Fortney (University of California, Santa Cruz, USA)\\
---Structure and Evolution of Gas Giant Planets
Andrea Ferrara (Scuola Normale Superiore, Italy)\\
---Star Formation in the Early Universe and the Transition from Population III to Populations II and I
Eline Tolstoy (University of Groningen, The Netherlands)\\
---Chemical Evolution of the Milky Way and Local Group Galaxies
Memorial Lecture for Prof. Chushiro Hayashi\\
Daiichiro Sugimoto (The University of Tokyo, Japan)
---The Discovery of Hayashi Phase and His Way of Thinking
Who are the target participants?\\
- The lectures are targeted on PhD students and post-docs\\
- Please note that this school is not for bachelor and diploma students\\
- All the lectures are in English and we welcome eligible applicants worldwide\\
How to apply?\\
- Please go to the following webpage\\
https://www.cps-jp.org/guestEntryPrivacypolicySimple.php?ml\_lang=en\\
First, create your CPS account at this page.\\
Then, go to CPS website https://www.cps-jp.org/ and login with your CPS User ID you have registered.\\
You will see 'CPS 7th International School of Planetary Sciences' at the right column. Click there and start registration application.
Important Dates:\\
All deadline times are 23:59 Japanese Standard Time, UTC+9\\
22 August 2010\hspace{5.2em} Travel Grant Application deadline\\
29 August 2010\hspace{5.2em} Registration Application deadline\\
9 September 2010\hspace{4.3em} Result Notification\\
27 November 2010\hspace{4.0em} Poster presentation abstract deadline\\
10-15 January 2011\hspace{3.5em} CPS 7th International School of Planetary Sciences
Advisory Committee\\
Ken-ichi Nomoto (IPMU, The University of Tokyo)\\
Hiroyasu Ando (National Astronomical Observatory of Japan)\\
Takashi Kozasa (Hokkaido University)\\
Hiromoto Shibahashi (The University of Tokyo)\\
Nobuo Arimoto (National Astronomical Observatory of Japan)\\
Toshitaka Kajino (National Astronomical Observatory of Japan)\\
Toshikazu Shigeyama (RESCEU, The University of Tokyo)\\
Issei Yamamura (ISAS/JAXA)\\
Wako Aoki (National Astronomical Observatory of Japan)\\
Masahiro Ikoma (Tokyo Institute of Technology)
Local Organizing Committee (* Chair, ** Scientific secretary, *** Secretary)\\
Masayuki Y. Fujimoto* (CPS, Hokkaido University)\\
Takuma Suda** (Hokkaido University)\\
Yutaka Katsuta** (Hokkaido University)\\
Nozomu Tominaga** (Konan University)\\
Hiroshi Kimura (CPS)\\
Ko-ichiro Sugiyama (CPS)\\
Yoshiyuki O. Takahashi (CPS)\\
Seiya Nishizawa (CPS)\\
Jun Kimura (CPS)\\
Ayako Suzuki (CPS)\\
Takayuki Tanigawa (CPS)\\
Ko Yamada (CPS)\\
Asako Sato*** (CPS)\\
Yoshiko Honjo*** (CPS)\\
Mire Murakami*** (CPS)\\
Mariko Hirano*** (CPS)\\
Yasuko Uematsu*** (CPS)
Program Committee\\
Masayuki Y. Fujimoto (CPS, Hokkaido University)\\
Toshikazu Shigeyama (RESCEU, The University of Tokyo)\\
Yoichi Itoh (CPS, Kobe University)\\
Yuri Aikawa (CPS, Kobe University)\\
Masahiro Ikoma (Tokyo Institute of Technology)\\
Takuma Suda (Hokkaido University)\\
Nozomu Tominaga (Konan University)
Contact us\\
E-mail: pschool-7info {\em at} cps-jp.org\\
Fax:+81 78 803 5731\\
Center for Planetary Science\\
1-1 Rokkodai, Nada, Kobe 657-8501, Japan
\vspace{2cm}
\begin{center}
{\Large\em Short Announcements}
\end{center}
\vspace*{0.6cm}
The refereeing process for the HIFI First Result special issue of A \&
A will conclude on July 31, 2010. As of this writing, a large number
of papers have already been accepted and are available through
Astroph. Together, these papers give a good impression of the
versatility of HIFI and the expected breadth of HIFI's impact on
astrophysics and astrochemistry. We want to alert you to the website,
{\bf http://hifi.strw.leidenuniv.nl/}, where we collect these papers and
provide relevant links to the teams webpages. As a service to the
community, we will add HIFI papers, as they are accepted for
publication, to this page throughout the mission. So, you might want
to bookmark this page as an easy entry point for HIFI results.
Xander Tielens\\
HIFI project scientist
\vspace{2cm}
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{ {\Large\bf Moving ... ??}\\
If you move or your e-mail address changes, please send the editor your
new address. If the Newsletter bounces back from an address for three
consecutive months, the address is deleted from the mailing list.
}}}
\end{center}
\end{document}
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%%% %%%
%%% Please use for abstracts of papers which have been ACCEPTED in %%%
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%%% or conference notes). Merely fill in the brackets below and %%%
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{\bf{ First Author$^1$, Second Author$^2$ \ and Third Author$^3$ }}
%% Here you write your institute name(s) and address(es),
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$^2$ {Cerro Tololo Inter-American Observatory, National Optical Astronomy
Observatories, Casilla 603, La Serena, Chile} \\
$^3$ {Las Campanas Observatory, Carnegie Inst. of Washington, Casilla
601, La Serena, Chile}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
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%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
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% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J. }
%% If preprints are available on the WWW you can give the web
%% direction here.
%\end{document}
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%%% have one full page for everything, and you are very welcome to
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%% Between these brackets you write the title of your thesis:
{\Large\bf{Title of Thesis}}
\vspace*{0.5cm}
%% Here comes your name
{\bf{ Author }}
%% Here you write the institute where your thesis work was conducted, e.g.:
{Thesis work conducted at: Steward Observatory, University of Arizona, USA}
%% Here comes your present postal address (if you are about to move and know
%% your coming address give it as well) e.g.:
{Current address: European Southern Observatory, Casilla 19001,
Santiago 19, Chile}
%% (if you use this part, remove %%)
%% {Address as of XX XXX 2002: }
%% Here comes your e-mail address:
{Electronic mail: doctor@sun.institute.edu}
%% Name of your adviser:
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%% Month and Year of thesis:
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